5Space🚀Scientists aboard a plane with 26 cameras chase burning satellite and film its fiery fallChris Young17 hours ago 9Military🚀China deploys 5,000-ton torpedo frigate to hunt US nuclear submarines in open seasKapil Kajal19 hours ago 10Military🚀UK gets drone wingmen to make F-35 fighters invisible to even the smartest radarsJijo Malayil20 hours ago 1Culture🌟Tech games: Elon Musk wins as Sam Altman's Open AI drops full-profit shift for nowSujita Sinhaan hour ago 4Culture🌟Trump’s secure messaging app hacked, deportation airline also hit by cyberattackAamir Khollam11 hours ago 5Energy🌟US scientists end 70-year fusion struggle, paving way for better reactorsAamir Khollam12 hours ago 7Science🌟In a first, protons in biological system seen following quantum rules: Study Mrigakshi Dixit13 hours ago 9Space🌟US orders NASA to build first lunar time zone to guide astronauts on the MoonAamir Khollam14 hours ago Abhishek Bhardwaj Max Planck Institute for Plasma Physics The world’s largest and most powerful stellarator is going to resume experimental operation from today at the Max Planck Institute for Plasma Physics (IPP) in Greifswald The stellarator had made headlines in February 2023 when it lasted eight minutes and delivered a power output of 1.3 gigajoules Wendelstein 7-X had been shut down as per plans and it has undergone maintenance Several new modules have also been added to the stellarator The new experiment phase OP2.2 will begin today Some of the improvements made to Wendelstein 7-X include the addition of updated control and data acquisition systems The team of researchers focused on improving the availability and reliability of the systems in place and a systematic failure mode analysis was also carried out for the same purpose The stellarator concept was invented by Lyman Spitzer at Princeton University in 1951 In the quest for achieving safe, clean, and renewable power, stellarators have emerged as one of the technologies which scientists think could lead to fusion energy at a commercial scale A stellarator is a machine that uses magnetic fields to confine plasma in the shape of a donut, called a torus. These magnetic fields allow scientists to control the plasma particles and create the right conditions for fusion, according to the US Department of Energy Some of the key benefits which stellarators offer over tokamaks are that they require less injected power to sustain the plasma and allow for simplification of some aspects of plasma control.  The Wendelstein 7-X is the world’s largest fusion device of the stellarator type It’s goal is to find out whether stellarators can be used for producing energy at a commercial scale The main assembly of Wendelstein 7-X was concluded in 2014 the first plasma was produced on December 10 On February 15, 2023, the researchers were able to achieve an energy turnover of 1.3 gigajoules using Wendelstein 7-X This was 17 times higher than the best value achieved before the conversion (75 megajoules).  The energy turnover of 1.3 gigajoule was achieved with an average heating power of 2.7 megawatts This was also a new record for Wendelstein 7-X and one of the best values worldwide The two most significant enhancements in the device are the addition of a heating element (gyrotron) which can generate significantly more than 1 megawatt of power into the plasma via microwaves The next is the addition of a new steady-state pellet injector “It is used to ensure the supply of hydrogen particles into the plasma – an important step on the way to a nuclear fusion power plant The pellet injector produces long rods of frozen hydrogen from which small pellets are regularly cut off at intervals of fractions of a second in order to shoot them into the plasma at high pressure The aim of the experiment is to gradually increase the performance parameters for the generated plasmas “We are gradually approaching higher heating powers,” says IPP Director Prof Thomas Klinger. “On the one hand the aim is to carefully test the heat load limits on the carbon walls of W7-X we want to understand turbulence-controlled transport processes in the plasma and the exhaust of heat and particles.” The W7-X team is not aiming for new records for the plasma duration but aims to increase the energy throughput “The aim is to achieve long pulses at high plasma temperatures And that’s what we’re working on right now,” Klinger added The experiment phase OP2.2 will run from September to December 2024 this will be followed by OP2.3 which will run from February to May 2025 This will be followed by a scheduled break for maintenance and experiments will resume under OP2.4 in August-December 2026 3COMMENTSABOUT THE AUTHORAbhishek Bhardwaj Abhishek brings a wealth of experience in covering diverse stories across different beats Having contributed to renowned wire agencies and Indian media outlets like ANI and NDTV By clicking sign up, you confirm that you accept this site's Terms of Use and Privacy Policy Premium a process in which two light nuclei combine to form a heavier nucleus that releases massive energy the magnetic confinement process requires heating a gas to create a plasma which is then confined by a powerful magnetic field a global leader in the design and manufacturing of plasma heating systems is the only European manufacturer of "Gyrotron" electronic tubes These high-power vacuum tubes are used to heat plasma to temperatures ten times greater than that of the sun's core This equipment is essential for initiating nuclear fusion reactions through magnetic confinement It was developed in collaboration with the European GYrotron Consortium (EGYC)2 autonomous European source of highly reliable gyrotrons Operating at a strategic nominal frequency of 140 gigahertz (GHz) theses reactors can also adapt to other frequencies is a cutting-edge research center for the study of nuclear fusion by magnetic confinement its activities focus on exploring and optimizing plasmas which can reach temperatures of several million degrees Celsius Wendelstein 7-X launched its experimental campaign "The world record set by our Gyrotron marks a significant milestone in the race for fusion and illustrates our commitment to technological innovation and excellence This technological breakthrough positions Thales at the forefront of high-power plasma heating solutions essential for addressing the energy challenges of tomorrow." said Charles-Antoine Goffin Vice President of Microwave & Imaging Sub-Systems at Thales Nuclear fusion is considered an opportunity to create a clean energy source as it does not generate greenhouse gases and is abundant as its resources being present in large quantities in nature It is therefore identified as one of the solutions to address two crucial challenges: the need to reduce global carbon emissions and the ever-growing demand for energy in various sectors of the economy 1 A stellarator is a magnetic confinement device used in nuclear fusion research It maintains a hot plasma by using a complex network of external coils to generate a helical magnetic field without requiring internal electrical current This configuration allows for continuous operation and reduces the risk of instabilities 2 The European Gyrotron Consortium (EGYC) includes the Swiss Plasma Center (SPC) the École Polytechnique Fédérale de Lausanne (EPFL) the Karlsruhe Institute of Technology (KIT) the Institute for Plasma Science and Technology of the Italian National Research Council (ISTP-CNR) Developed in collaboration with the Max Planck Institute for Plasma Physics specifically for the Wendelstein 7-X stellarator Thales's TH1507U gyrotron has achieved a significant milestone by reaching a total output of 1.3 megawatts in radiofrequency at a frequency of 140 gigahertz for 360 seconds A gyrotron is a high-powered linear beam vacuum tube that generates millimeter-wave electromagnetic waves by the cyclotron resonance of electrons in a strong magnetic field Thales's gyrotron plays a crucial role in the Wendelstein 7-X stellarator project by providing heating and stabilisation of the plasma which are essential for reaching the temperatures required for magnetic confinement nuclear fusion The Wendelstein 7-X project - the world's largest and most powerful stellarator - not only aims to enhance the fundamental understanding of plasmas but also to contribute to the development of commercial fusion reactors Munich-based Thales is the only European manufacturer of gyrotron electronic tubes The TH1507U gyrotron was developed in collaboration with the European GYrotron Consortium which aims to create an autonomous European source of highly reliable gyrotrons Operating at a strategic nominal frequency of 140 gigahertz these reactors can also adapt to other frequencies "The world record set by our gyrotron marks a significant milestone in the race for fusion and illustrates our commitment to technological innovation and excellence," said Charles-Antoine Goffin vice president of Microwave & Imaging Sub-Systems at Thales "This technological breakthrough positions Thales at the forefront of high-power plasma heating solutions essential for addressing the energy challenges of tomorrow." After Wendelstein 7-X generated a record plasma in February 2023 (lasting 8 minutes with an energy output of 1.3 gigajoules) the stellarator at the Max Planck Institute for Plasma Physics in Greifswald was shut down as planned for maintenance and improvements including the installation of the new gyrotron Wendelstein 7-X started a new experimental campaign the Wendelstein 7-X – the world’s largest stellarator-type fusion device at Max Planck Institute for Plasma Physics (IPP) in Greifswald Germany – produced its first hydrogen plasma At the push of a button by Federal Chancellor Angela Merkel a 2-megawatt pulse of microwave heating transformed a tiny quantity of hydrogen gas into an extremely hot low-density hydrogen plasma This entails separation of the electrons from the nuclei of the hydrogen atoms Confined in the magnetic cage generated by Wendelstein 7-X the charged particles levitate without making contact with the walls of the plasma chamber The plasma reached a temparature of 80 million degrees and a lifetime of a quarter of a second The present initial experimentation phase will last till mid-March The plasma vessel will then be opened in order to install carbon tiles for protecting the vessel walls and a so-called “divertor” for removing impurities “These facilities will enable us to attain higher heating powers and longer discharges lasting up to ten seconds” discharges lasting 30 minutes can be produced and it can be checked at the full heating power of 20 megawatts The objective of fusion research is to develop a power plant favourable to the climate and environment that derives energy from the fusion of atomic nuclei just as the sun and the stars do only a tokamak is thought to be capable of producing energy-supplying plasma and this is the international test reactor ITER which is currently being constructed in Cadarache (France) in the frame of a worldwide collaboration Are you a LinkedIn user who would like to follow the latest hydrogen news on a more regular basis? Then our LinkedIn weekly newsletter may be what you’re looking for. You can subscribe to it here.  PS: Would you like to follow the latest hydrogen news on a more regular basis? Then you should subscribe to our newsletters: “your hydrogen news live” (to receive all our articles as soon as they are published) and “your weekly newsletter” (sent every Monday morning).  info@hydrogentoday.info Home Newsletters Calendar Hydrogen in the world Key players in hydrogen Our fact sheets about hydrogen © Copyright – Communicaweb 2025 Legal noticies – Management of personal data  New ITER Boutique! Purchase ITER-branded merchandise here ITER NewslineKeep in touch with ITER through our main news feed ITER Magazine - French onlyLearn more about the ITER Project by subscribing to this quarterly online magazine (in French) that is geared toward the general public ITER Open Doors Day - NotificationsStay informed about the ITER Open Doors sessions and be among the first to subscribe to the next event the Wendelstein 7-X stellarator has reached (and passed) a target, achieving an energy turnover of 1.3 gigajoules the hot plasma was maintained for eight minutes ITER ("The Way" in Latin) is one of the most ambitious energy projects in the world today ITER is charting new territory in fusion research Metrics details A Publisher Correction to this article was published on 12 October 2021 This article has been updated Here we demonstrate that such record values provide evidence for reduced neoclassical energy transport in W7-X as the plasma profiles that produced these results could not have been obtained in stellarators lacking a comparably high level of neoclassical optimization T is its temperature and τE is the energy confinement time where W is the stored plasma energy and P is the heating power provided by fusion reactions The temperature dependence of the fuel’s fusion reactivity provides an additional constraint; for deuterium–tritium fusion this reactivity falls rapidly below a temperature of 10 keV (≈1.2 × 108 K) High temperatures are thus mandatory in fusion plasmas but must be simultaneously consistent with a tolerable level of energy transport if the required τE is to be achieved the neoclassical energy flux through the magnetic surface with a minor radius of r will obey \(V{\prime} {Q}_{{\rm{neo}}}\propto {n}^{2}{T}^{1/2}{B}_{0}^{-2}\) where the left-hand side of this expression is the product of magnetic surface area and flux-surface-averaged neoclassical energy-flux density and where B0 is the average magnetic field strength at the major radius of the plasma axis (denoted by R0) This is noteworthy as these scalings are identical to those of the classical case and the temperature dependence is therefore benign and as neoclassical and turbulent losses are additive the former are generally ignored when assessing the overall energy confinement to be expected in a tokamak reactor The situation is very different in a high-temperature stellarator plasma ϵeff will have the same value as the helical-ripple amplitude for the limiting case in which this amplitude is a constant over the entire flux surface localized particles are also responsible for the appearance of a radial electric field which must arise in stellarators to establish ambipolarity of the neoclassical particle fluxes (meaning that no net radial current flows in the plasma) This electric field introduces an E × B drift into the particles’ equation of motion which causes localized particles to drift poloidally with a precession frequency ΩE ≈ |Er|/(rB0) thereby placing an additional limit on the radial excursion of orbits This poloidal precession is more important than collisions for particles that have ΩE > νeff where νeff is the frequency with which collisional removal from the ripple occurs the collision frequency of electrons will exceed that of the ions by roughly two orders of magnitude and the ions will not be subject to 1/ν transport but will instead have their orbits constrained by ΩE with a value of Er such that the neoclassical ion particle flux is reduced to the value for electrons a more detailed presentation of neoclassical results is provided in Methods it is demonstrated that strong reduction of electron 1/ν transport is also of direct benefit for reducing energy fluxes in the ion channel but experimental verification in W7-X is required for certainty Radial profiles of ϵeff are shown for the W7-X standard (black continuous curve) and high-mirror (black broken curve) configurations as well as for the LHD R0 = 3.6 m (red continuous curve) and R0 = 3.75 m (red broken curve) configurations the ‘missing’ portion of the curve that extends above the plot area increases roughly quadratically with normalized minor radius to reach a value of 0.225 at ρ = 0.93 plasma performance in W7-X is commonly limited by turbulence as well and an experimental assessment of the neoclassical energy confinement in this device therefore requires a plasma scenario for which the turbulent transport is reduced The strong temperature dependence of stellarator neoclassical energy transport immediately raises the question of whether such record triple-product results are also experimental evidence for the reduction of neoclassical energy losses by optimization of the W7-X magnetic field This discharge is particularly attractive for such an investigation as the 1.02 MJ are maintained for a full energy confinement time of 230 ms thereby simplifying the plasma energy balance as the ∂W/∂t term appearing in this equation will be of negligible importance by the end of the high-energy phase further details of this experiment can be found in Methods Thomson scattering measurements of ne and Te are shown by red data points ECE results for Te are plotted in black and CXRS values of Ti are given by blue circles Error bars depict one standard deviation in the evaluation of the measurements Fits to the experimental data used in the neoclassical analysis are depicted by the continuous curves with red used for the electron profiles and blue for the ions The last closed flux surface of the equilibrium is at r = 0.508 m there are no published claims of experimental results for which the observed confinement exceeds neoclassical predictions More detailed results for each configuration are provided in the individual plots ion fluxes in blue and their sum appears as the black ball-and-chain curve Also depicted are results for the sum of electron and ion fluxes obtained from a temperature-sensitivity study at constant pressure by replacing (ne, Tα) with (gne, g−1Tα) and varying g from 0.9 (upper extent of the shaded region) to 1.1 (lower extent) Further details of the neoclassical results are provided for each individual configuration in the remaining four frames of Fig. 3 constituent contributions to the neoclassical energy fluxes made by electrons respectively; their sum is again given by the black ball-and-chain curve To illustrate the sensitivity of this sum to variations in plasma parameters results for the total neoclassical energy fluxes are also depicted with (ne g−1Tα) and varying the scaling factor g in the range 0.9 ≤ g ≤ 1.1 where α = {e, i} indicates the values for electrons and ions As the pressure profile is unaffected by this variation it is possible to perform all calculations using the same equilibrium The values of collisionality remain sufficiently small in all these cases to ensure that the electron neoclassical fluxes are predominantly due to 1/ν transport Given the strong temperature dependence of the losses in this regime it is apparent that \({Q}_{{\rm{neo}}}^{{\rm{e}}}\) will attain its largest value for g = 0.9 and then decrease as g increases The same behaviour is found for \({Q}_{{\rm{neo}}}^{{\rm{i}}}\) although the relative reduction is much weaker and can only be accounted for accurately by enforcing the ambipolarity constraint so as to obtain the correct value of the radial electric field The sum \({Q}_{{\rm{neo}}}^{{\rm{e}}}+{Q}_{{\rm{neo}}}^{{\rm{i}}}\) is thus a monotonically decreasing function of g over the range of values considered and confirms the theoretical expectations mentioned in the previous section As expected qualitatively, the results of Fig. 3 confirm that \(V{}^{{\prime} }({Q}_{{\rm{n}}{\rm{e}}{\rm{o}}}^{{\rm{e}}}+{Q}_{{\rm{n}}{\rm{e}}{\rm{o}}}^{{\rm{i}}})\) is an increasing function of ϵeff but quantification of this statement is far more difficult comparing the results of the two W7-X configurations one finds \({Q}_{{\rm{neo}}}^{{\rm{e}}}\) larger in the high-mirror case by a factor of five which corresponds well with the \({{\epsilon }}_{{\rm{eff}}}^{3/2}\) dependence of 1/ν transport the total neoclassical energy flux for W7-X high-mirror is increased by a factor only somewhat larger than two owing to the much smaller increase in \({Q}_{{\rm{neo}}}^{{\rm{i}}}\) This example also demonstrates the nonlinearity of the neoclassical fluxes—quantitative accuracy in the determination of these fluxes cannot rely only on comparisons of ϵeff reduction of all neoclassical fluxes and flows in line with the W7-X optimization goals is also substantiated These W7-AS discharges were heated using a combination of ECRH and neutral beam injection (NBI) the latter providing the plasma with a strong central particle source while simultaneously the edge particle source due to recycling neutrals dropped to unusually low levels steep density gradients could be maintained throughout the 250-ms heating pulse but such pulses were insufficient to claim ‘steady-state’ conditions as the sinks due to neutral-particle pumping by plasma-facing components did not saturate during this time NBI was successfully commissioned during the second portion of the 2017–2018 campaign and will allow future investigations into whether optimum confinement conditions can also be realized in this device during the 10-s duration of NBI pulses To truly test the steady-state perspectives of the HELIAS concept the ECRH at W7-X has been designed to provide the plasma with 1,800 s of continuous-wave power and a water-cooled high-heat-flux divertor is currently being installed in the device to provide the necessary particle and heat exhaust over this period of time If steep density gradients are indeed the key to improving the confinement of W7-X plasmas density profile tailoring over such time scales will probably need to rely on the capabilities of a new steady-state pellet injector which should also go into operation during the next campaign temperature and charge of the given species Er = Er(r) is the radial electric field and the δij are normalized transport coefficients comprising appropriate combinations of elements of the neoclassical transport matrix where K ≡ κ/T = mv2/(2T) is the normalized kinetic energy and D is the so-called mono-energetic radial transport coefficient The terminology ‘radial’ is used here to denote quantities that are oriented perpendicularly to flux surfaces so that the radial coordinate r should be understood as a flux-surface label To understand how the neoclassical energy transport scales with various plasma and configuration parameters it is sufficient to consider a simple heuristic description of random-walk diffusion processes having D ∝ ℱ(Δr)2νeff where ℱ is the fraction of particles participating in the process Δr is the characteristic step size of such particles and νeff is the frequency with which a step is taken the transport is due to the pitch-angle scattering portion of the linearized collision operator allowing one to express the ‘effective’ step frequency as νeff = ν/ℱ2 where ν is the 90°-deflection frequency and the ℱ−2 enhancement accounts for the fact that scattering through the portion of phase space comprising ℱ occurs more often than scattering through 90° The heuristic expression for the transport coefficient then simplifies to D ∝ (Δr)2ν/ℱ leaving only Δr and ℱ to be determined which is a largely geometric factor reflecting the topology of the local maxima of B Substitution of these quantities into the heuristic expression for the transport coefficient then yields for the ions \(D\propto {({v}_{{\rm{d}}}/{\varOmega }_{E})}^{2}\nu {(\sqrt{\nu /{\varOmega }_{E}}+{ {\mathcal F} }_{{\rm{t}}{\rm{r}}})}^{-1}\) which is more commonly found in the literature as two separate results for the limiting cases in which one of the terms within the parentheses is far larger than its counterpart the so-called √ν regime with \(D\propto {v}_{{\rm{d}}}^{2}\,{(\nu /{\varOmega }_{E}^{3})}^{1/2}\) and the ‘ν regime’ with \(D\propto {({v}_{{\rm{d}}}/{{\Omega }}_{E})}^{2}\nu /{ {\mathcal F} }_{{\rm{tr}}}\) Using \({\mathscr{A}}\) to signify those parameters in ν/ΩE that are not of direct relevance to plasma-parameter scalings the neoclassical ion energy losses are then seen to obey Although this expression is conveniently compact it leaves the complicated dependence of Er on plasma and device parameters unspecified This will be addressed next for the case of most relevance to the reduction of neoclassical transport in W7-X neoclassical particle fluxes are not intrinsically ambipolar in a stellarator and thus a theoretical means of determining the Er profile is provided by enforcing the ambipolarity constraint In a pure hydrogen plasma (using α = e to denote electrons and α = i for ions) for which ne = ni = n and for which qe = −e and qi = e equating \({{\Gamma }}_{{\rm{neo}}}^{{\rm{e}}}\) and \({{\Gamma }}_{{\rm{neo}}}^{{\rm{i}}}\) will yield Substituting this result back into the neoclassical expressions where the species indices are chosen to be [α, β] = [e, i] or [i, e] as appropriate one should recall that the \({L}_{ij}^{{\rm{i}}}\) are dependent on Er so that profitable use of these equations requires that special circumstances hold One such example is the fusion-relevant case that has Te = Ti = T for which the radial electric field equation becomes and will yield Er ∝ T for the limiting case in which electron 1/ν transport has been sufficiently reduced to satisfy \({L}_{11}^{{\rm{e}}}/{L}_{11}^{{\rm{i}}}\ll 1\) the particle flux density is well approximated by When these limits apply one obtains \(25\le {\delta }_{22}^{{\rm{e}}}+{\delta }_{12}^{{\rm{i}}}{\delta }_{21}^{{\rm{e}}}\le 115/4\) and \(2\le {\delta }_{22}^{{\rm{i}}}-{\delta }_{12}^{{\rm{i}}}{\delta }_{21}^{{\rm{i}}}\le 11/4\) so that the δij combination of relevance for electrons is an order of magnitude larger than its counterpart for ions The neoclassical energy transport of electrons and ions will thus be of similar magnitudes and the strong reduction of \({L}_{11}^{{\rm{e}}}\) is clearly seen to be of benefit to both species which is used to prepare a dataset of mono-energetic transport coefficients covering the entire range of ν* and Er values relevant for determining the Lij given any combination of density and temperature producing the pressure profile of the VMEC equilibrium The radial electric field profile is determined self-consistently by using numerical root-finding techniques to determine solutions to the nonlinear ambipolarity constraint This deleterious effect can be counteracted to an extent by using the vertical field coils to shift the plasma axis back to its vacuum position but a deformation in the shape of flux surfaces remains which serves to degrade the neoclassical confinement The neoclassical energy losses calculated here for LHD are thus ‘best case’ results the W7-X optimization had the explicit goal of using finite-plasma-pressure effects to its benefit; for the high-mirror configuration ϵeff decreases monotonically as the pressure increases small-to-modest pressure has little influence on this quantity 640 MW for LHD R0 = 3.6 m and 1,320 MW for LHD R0 = 3.75 m ion neoclassical energy fluxes are at least as large as those of the electrons but even the somewhat extreme assumption of \({Q}_{{\rm{neo}}}^{{\rm{i}}}=2{Q}_{{\rm{neo}}}^{{\rm{e}}}\) would make the total neoclassical energy fluxes only a fraction of the α-particle heating for W7-X standard the reactor prospects of W7-X high-mirror appear questionable but one must realize that this back-of-the-envelope estimate ignores changes to the configuration due to increased plasma pressure ϵeff in the high-mirror configuration is reduced by enough that \({Q}_{{\rm{neo}}}^{{\rm{e}}}\) would drop by a factor of two For the LHD cases it is necessary to choose different scaling factors; the R0 = 3.6 m case becomes viable with a factor five larger size and the somewhat reduced temperature that this allows (This assumes that the vertical field coils of the heliotron are used to compensate the Shafranov shift as the neoclassical transport in such a high-pressure equilibrium would otherwise become intolerable) It should also be pointed out that the optimization of W7-X was undertaken roughly thirty years ago and that great improvements in the projected fast-particle confinement of HELIAS have been made in the intervening years Such improvements have simultaneously reduced the ϵeff values from the per cent level of W7-X to the per mille level in new reactor candidates thereby decreasing neoclassical energy transport for prospective fusion plasmas to very small levels coupled with the predominance of turbulent transport in the W7-X experiment have focused recent theoretical and numerical efforts on the further optimization of the HELIAS concept to also contend with this transport channel and it is not yet possible to foresee what combination of optimized magnetic field and plasma conditions will best reduce turbulent transport and what influence such a combination will have on the other HELIAS optimization goals The gyrotron frequency of 140 GHz is resonant at the second harmonic for a magnetic field strength of B = 2.5 T with cutoff densities of nc = 1.2 × 1020 m−3 for waves with extraordinary-mode (X2) polarization and 2nc for ordinary-mode (O2) polarization At these densities and for W7-X plasma volumes of nearly 30 m3 the collisional transfer of energy from electrons to ions should be excellent so that Ti ≈ Te can be expected in spite of lacking a direct means of heating the ions Such operational conditions also mimic qualitatively those of a reactor where the heating power of fusion α-particles goes chiefly to electrons which subsequently heat deuterium and tritium ions by collisional energy exchange early in the second half of the TDU campaign considerable increases of the plasma diamagnetic energy were measured in the aftermath of pellet fuelling and the discharge 20180918.045 is used here to illustrate such results the ECRH power is increased to 4.5 MW to maintain Te at values sufficient for good O2 absorption This is further aided at W7-X by a multi-pass launch scheme which uses specially prepared reflecting surfaces to redirect unabsorbed ECRH power back into the plasma ray-tracing simulations predict that more than 95% of the launched ECRH power will be deposited in the plasma during the high-performance phase of discharge 20180918.045 a value that has been confirmed by the analysis of stray-radiation measurements from the experiment taken with ‘sniffer’ probes Te falls and the central electron temperature has dropped below 2 keV—nearly to the level of central Ti—when the increase in ECRH power occurs pellet fuelling has been accompanied by a rise in the diamagnetic energy from Wdia = 0.40 MJ at t = 1.8 s to Wdia = 0.68 MJ at t = 1.8 s the time rate of change of Wdia then increases considerably and the diamagnetic energy attains its maximum value of 1.02 MJ after another 400 ms the line-integrated density decreases throughout this time making it evident that a temperature increase must also have taken place and the central values exceed 2.5 keV for both electrons and ions an experimental situation has arisen that has high density and high temperatures simultaneously a situation ideal for testing the efficacy of the W7-X optimization regarding reduction of the neoclassical transport The discharge shown here is particularly attractive for such an investigation as the 1.02 MJ are maintained for 230 ms which corresponds to one energy confinement time given the 4.5 MW of ECRH used to heat the plasma This simplifies considerations of the energy balance as the ∂W/∂t term appearing in this equation will be of negligible importance by the end of the high-energy phase It encircles the plasma and is equipped with four compensation coils which are also located inside the vacuum vessel and directly attached to the diamagnetic loop itself These do not encircle the plasma and can therefore be used to compensate measurements of the main loop for errors due to eddy currents in the adjacent vacuum vessel as well as fluctuations of externally driven currents in the main superconducting magnetic field coils The probing beam passes through the plasma twice by making use of a corner cube reflector; the single-pass path length through the plasma is roughly 1.3 m The statistical error for ∫dℓne is generally given as 1018 m−2 and there was an additional systematic error ≤4 × 1018 m−2 during the portion of the experimental campaign during which discharge 20180918.045 was performed including compensation for spherical aberrations and the sub-pixel distribution of photons on the detector At the time point analysed for this discharge the XICS values of Ti exceed those of CXRS by 150 to 200 eV and indicate Ti > Te for r > 0.2 m despite the fact that no direct heating of the ions occurs using ECRH This is at odds with energy balance considerations which argue for Ti ≈ Te outside the region of power deposition These expectations are better fulfilled by the CXRS data and given the strong dependence of the neoclassical losses on temperature it has therefore been decided to err on the side of caution by using only the CXRS values of Ti for the profile fits used in the calculations of neoclassical fluxes The time evolution of the Ti profile measured by CXRS has also been confirmed through the measurements of the XICS system Line-integrated signals from 65 channels are used to obtain radiation intensity distributions by tomographic reconstruction with ‘relative gradient smoothing’ as regularization functional (to be published) Flux-surface-averaged radial emissivity profiles are then derived by averaging these 2D-emissivity distributions in the poloidal direction The total radiated power loss is a linear interpolation of radiation from the observation volume to that of the entire plasma volume Toroidal variations of the radiation strength are not considered an assumption supported by the results of edge modelling The data depicted in the plots of this paper and other findings of this study are available from the corresponding author upon reasonable request A Correction to this paper has been published: https://doi.org/10.1038/s41586-021-04023-y Modular stellarator reactors and plans for Wendelstein 7-X First results from divertor operation in Wendelstein 7-X Performance of Wendelstein 7-X stellarator plasmas during the first divertor operation phase Some criteria for a power producing thermonuclear reactor On the motion of a charged particle in a magnetic field The guiding center approximation to charged particle motion Transport phenomena in a collisionless plasma in a toroidal magnetic system Theory of plasma transport in toroidal confinement systems Invariance principles and plasma confinement A stellarator coil system without helical windings Plasma diffusion in a toroidal stellarator Monte-Carlo simulations of neoclassical transport in stellarators Ripple transport in helical-axis advanced stellarators: a comparison with classical stellarator/torsatrons Physics and engineering design for Wendelstein 7-X Transport analysis of stellarator reactors 407–418 (International Atomic Energy Agency Transport processes and entropy production in toroidal plasmas with gyrokinetic electromagnetic turbulence Theory of plasma confinement in non-axisymmetric magnetic fields Physics in the magnetic configuration space of W7-X Benchmarking of the mono-energetic transport coefficients — results from the International Collaboration on Neoclassical Transport in Stellarators (ICNTS) Pellet fueling experiments in Wendelstein 7-X High-performance plasmas after pellet injections in Wendelstein 7-X Inter-machine validation study of neoclassical transport modelling in medium- to high-density stellarator-heliotron plasmas Conceptual design of a compact helical fusion reactor FFHR-c1 for the early demonstration of year-long electric power generation Investigation of the neoclassical ambipolar electric field in ion-root plasmas on W7-X Magnetic configuration effects on the Wendelstein 7-X stellarator Suppression of electrostatic micro-instabilities in maximum-J stellarators Effect of collisionless detrapping on non-axisymmetric transport in a stellarator with radial electric field Density control problems in large stellarators with neoclassical transport Three-dimensional free boundary calculations using a spectral Green’s function method Variational bounds for transport coefficients in three-dimensional toroidal plasmas Equilibrium of a toroidal pinch in a magnetic field The effect of finite β on stellarator transport Study of neoclassical transport in LHD plasmas by applying the DCOM/NNW neoclassical transport database Electron cyclotron heating for W7-X: physics and technology Blower gun pellet injection system for W7-X Plasma ion heating by cryogenic pellet injection Diamagnetic energy measurement during the first operational phase at the Wendelstein 7-X stellarator Real-time dispersion interferometry for density feedback in fusion devices The Thomson scattering system at Wendelstein 7-X The Thomson scattering diagnostic at Wendelstein 7-X and its performance in the first operation phase ECE diagnostic for the initial operation of Wendelstein 7-X In 20th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating (EC20) (eds Oosterbeek Bayesian modeling of microwave radiometer calibration on the example of the Wendelstein 7-X electron cyclotron emission diagnostic Höfel, U. Bayesian Analysis of Electron Cyclotron Emission Measurements at Wendelstein 7-X. PhD thesis, Technische Universität Berlin (2020); https://doi.org/10.14279/depositonce-9621 Charge exchange recombination spectroscopy at Wendelstein 7-X Objectives and layout of a high-resolution X-ray imaging crystal spectrometer for the Large Helical Device Tomographic inversion techniques incorporating physical constraints for line integrated spectroscopy in stellarators and tokamaks Prospects of X-ray imaging spectrometers for impurity transport: recent results from the stellarator Wendelstein 7-X First observation of a stable highly dissipative divertor plasma regime on the Wendelstein 7-X stellarator Download references This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 and 2019–2020 under grant agreement no The views and opinions expressed herein do not necessarily reflect those of the European Commission Open access funding provided by Max Planck Society Present address: Fritz-Haber-Institut der Max-Planck-Gesellschaft École royale militaire/Koninklijke Militaire School (ERM/KMS) Institute for Energy and Climate Research – Plasma Physics Ioffe Physical-Technical Institute of the Russian Academy of Sciences Institute of Plasma Physics and Laser Microfusion Institute for Surface Process Engineering and Plasma Technology Physikalisch Technische Bundesanstalt (PTB) Istituto di Fisica del Plasma “Piero Caldirola” planned and coordinated the experiment described here provided the ECRH power and its deposition profile calculated the unabsorbed ECRH power using sniffer probe data Svensson provided experimental data for the effective charge state or helped in analysis of this data supplied measurements of the diamagnetic energy provided data concerning the pellet series created the DKES datasets and performed the calculations of neoclassical fluxes determined the profiles of effective helical ripple created the figures (except for Extended Data Fig 1) and is the principal author of this paper with contributions to the body of the text from P.H. and with text concerning the diagnostics from K.J.B. provided the depiction of the W7-X non-planar coils Particle orbit videos were prepared by M.B All authors provided feedback and contributed to improving the paper The authors declare no competing interests Peer review information Nature thanks Dennis Whyte and the other reviewer(s) for their contribution to the peer review of this work Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations The complete set of superconducting coils also includes 20 planar coils which are used to change the rotational transform and/or shift the plasma column; these are not shown as they remain current-free for the configurations considered here as well as the radiated power measured by bolometers (dotted curve) The second frame plots the line-integrated density measured by an interferometer The third frame depicts ‘core’ electron (red) and ion (blue) temperatures from Thomson scattering and XICS measurements The diamagnetic energy trace during this discharge is given in the bottom frame A series of 28 pellets is injected into the plasma at a frequency of 30 Hz during the time phase indicated in grey Wdia values exceeding 1.02 MJ are recorded during the phase indicated in yellow This file contains detailed notes regarding Supplementary Videos 1 and 2 Localized ion trajectory in the W7-X standard configuration – see Supplementary Information document for detailed description Localized ion trajectory in the LHD configuration having a major radius of 3.75 m - see Supplementary Information document for detailed description Download citation DOI: https://doi.org/10.1038/s41586-021-03687-w Anyone you share the following link with will be able to read this content: a shareable link is not currently available for this article Sign up for the Nature Briefing newsletter — what matters in science After successful recommissioning in autumn 2022 the Wendelstein 7-X stellarator fusion device at Germany's Max Planck Institute for Plasma Physics (IPP) has achieved some significant breakthroughs an energy turnover of 1 gigajoule was targeted but researchers have now achieved 1.3 gigajoules a new record for discharge time was achieved with the hot plasma maintained for eight minutes the Wendelstein 7-X stellarator fusion device at Germany’s Max Planck Institute for Plasma Physics (IPP) has achieved some significant breakthroughs Wendelstein 7-X is the world’s largest stellarator fusion device Its goal is to investigate the suitability of such facilities for power production Stellarators differ from a tokamak fusion reactor such as the Joint European Torus (JET) in the UK or ITER under construction in France While a tokamak is based on a uniform toroidal shape a stellarator twists that shape in a figure eight This avoids problems tokamaks face when magnetic coils confining the plasma are necessarily less dense on the outside of the toroidal ring The main assembly of Wendelstein 7-X was completed in 2014 and first plasma was produced in December 2015 experiments were temporarily terminated after two successful work phases Upgrading of the plasma vessel was then started Wendelstein 7-X was primarily equipped with water cooling for the wall elements and an upgraded heating system The heating system can now couple twice as much power into the plasma as before and nuclear fusion experiments can be operated in new parameter ranges “We are now exploring our way towards ever higher energy values,” explained Professor Dr Thomas Klinger head of the Stellarator Transport & Dynamics Division at IPP we have to proceed step by step so as not to overload and damage the facility.” The researchers have now reached a new milestone: for the first time they were able to achieve an energy turnover of 1.3 gigajoules – 17 times higher than the best value achieved before the conversion (75 megajoules) The energy turnover results from the coupled heating power multiplied by the duration of the discharge Infrared images from the Wendelstein 7-X vacuum vessel do not show the plasma itself but the temperature distribution at the water-cooled divertor baffles The divertor baffles are used to dissipate the heat from the plasma This is where the plasma touches the divertor and the temperature is highest temperatures of up to 600 degrees Celsius were reached (red areas) The divertor tiles can withstand temperatures of up to 1200 degrees Celsius Particularly heat-resistant divertor baffle plates are used to dissipate the largest heat flows which is now cooled by a system of 6.8 kilometres of water pipes since the completion of the device No other fusion facility in the world currently has such a comprehensively cooled inner wall The plasma heating consists of three components: the newly installed ion heating the heating by neutral particle injection and electron microwave heating the electron microwave heating system was particularly important because it delivers large amounts of power over periods of several minutes The energy turnover of 1.3 gigajoule was achieved with an average heating power of 2.7 MW This is also a new record for Wendelstein 7-X and one of the best values worldwide Wendelstein 7-X achieved maximum plasma times of 100 seconds at much lower heating power the plan is to increase the energy turnover to 18 gigajoules with the plasma then being kept stable for half an hour Image: Infrared image from the vacuum vessel of Wendelstein 7-X showing the temperature distribution at the water-cooled divertor baffles (courtesy of MPI for Plasma Physics) Give your business an edge with our leading industry insights View all newsletters from across the Progressive Media network © Business Trade Media International Limited This website is using a security service to protect itself from online attacks The action you just performed triggered the security solution There are several actions that could trigger this block including submitting a certain word or phrase You can email the site owner to let them know you were blocked Please include what you were doing when this page came up and the Cloudflare Ray ID found at the bottom of this page Department of Energy has awarded grants to University of Wisconsin-Madison engineers to lead three research projects at Wendelstein 7-X (W7-X) a major fusion energy facility located in Germany The UW-Madison awards are part of $6.4 million in total DOE funding for seven projects announced in June 2021 for research on two international fusion energy stellarator facilities—W7-X and the Large Helical Device (LHD) in Japan one of the principal investigators on the grants These collaborations enable graduate students, post-docs and scientists from the College of Engineering to explore critical science and technology issues at the frontiers of magnetic fusion research using the unique capabilities of the most advanced overseas research facilities Fusion energy research seeks to harness the energy that powers the sun and stars as a clean Stellarators are fusion facilities that promise steady state highly-efficient plasma confinement with minimal control needs all assets for the economic operation of future fusion energy plants The funded projects at W7-X will continue the major U.S advance understanding of magnetic confinement and address research priorities critical to the W7-X mission The projects were selected by competitive peer review under the DOE Funding Opportunity Announcement for Collaborative Research in Magnetic Fusion Energy Sciences on Long-Pulse International Stellarator Facilities two post-docs and one professional engineer is involved in the effort Plasma turbulence is an important loss mechanism for the energy and particles that are confined in a fusion device Researchers are studying innovative ways to optimize the plasma confinement by reducing turbulent transport which could enable stellarators to potentially obtain unprecedented levels of energy and particle confinement that would make a stellarator fusion reactor more effective and hence more economic Two of the projects deal with UW-Madison innovation for turbulent transport studies at W7-X Engineering Physics Assistant Professor Benedikt Geiger (PI), Engineering Physics Professor Chris Hegna (co-PI) and Assistant Scientist Ben Faber (co-PI) received $762,000 for their proposal “Exploring ion heat transport during neutral beam heated plasmas at W7-X.” The researchers will perform studies of turbulent heat transport in W7-X since recent results from W7-X show that the required excellent ion heat confinement is only observed during transient phases and in presence of peaked density profiles Stabilization of this promising regime of enhanced plasma confinement is a central quest of the next campaign at W7-X Geiger’s team will perform dedicated experiments to steer the level of heat injected into the plasma and the associated heat transport out of the plasma These experimental results will be compared to recent state-of-the-art turbulent transport modeling results from Hegna’s research group The efforts aim to apply new insights into turbulent transport optimization in the highly-shaped stellarator magnetic field configuration gained at UW-Madison to W7-X in order to accelerate the path to fusion energy will implement a BES diagnostic system at W7-X Their renewal grant follows a feasibility study that identified a viable diagnostic configuration and estimated diagnostic performance metrics UW-Madison scientists will work with collaborators in Germany to develop optical views for BES measurements and custom photodetectors with high sensitivity and high bandwidth will be developed at UW-Madison This diagnostic development draws from broad campus expertise in the area Optical design and detector fabrication is being conducted in collaboration with Distinguished Instrument Innovator Kurt Jaehnig (UW-Madison Department of Astronomy) and Distinguished Scientist Daniel Den Hartog (UW-Madison Department of Physics) These three grants are funding a total of five PhD students two post-doctoral fellows and two scientists The funds enable transfer of UW-Madison innovation in stellarator science and technology to the large-scale This partnership brings fusion one step closer to reality and involves the UW-Madison College of Engineering graduate research program at the front of this research enterprise Scientists toiling away on the cutting edge Wendelstein 7-X nuclear fusion reactor in Germany have pulled together results from their latest round of testing with a few records to be found amongst them the team is reporting the experimental device has achieved its highest energy density and the longest plasma discharge times for device of this type marking another step forward in the quest for clean fusion power Can something like the Wendelstein 7-X someday be used as part of a zero-emission power plant Like other experimental nuclear fusion reactors it is designed to recreate the reaction that takes place in stars The idea is to use magnetic fields to suspend a heated stream of plasma long enough for atomic nuclei within it to fuse together releasing tremendous amounts of energy in the process But holding a stream of plasma in place with magnetic fields isn't easy, especially when it needs to reach temperatures hotter than the Sun. For some time, scientists pursued this through what are known as tokamak fusion reactors simpler devices built to suspend the plasma stream inside a chamber in nicely rounded doughnut-like shape Wendelstein 7-X is what is known as a stellarator nuclear reactor it takes a highly complex form using 50 superconductive magnetic coils to hold plasma inside a containment field that twists and turns through an irregular loop It is hoped this approach can prevent the plasma streams drifting into the outer walls of the reactor and collapsing Though the idea of a stellarator first bobbed up at Princeton way back in 1951 the calculations they require were seen as too complex to realistically entertain until the arrival of the supercomputer Even then the Wendelstein 7-X took 15 years to put together but the result is the largest and most sophisticated stellarator device the world has ever seen Now the team says its latest round of experiments have achieved long-lasting plasmas of more than 100 seconds for the first time they are also reporting unprecedented energy yields brought on by newly installed components that inject fast hydrogen atoms into the plasma stream This resulted in high plasma densities of 2 x 1020 particles per cubic meter are values sufficient for a future power station The energy content of the plasma exceeded 1 megajoule for the first time ever exceeding the Sun's temperature of 15 million °C ( 27 million °F) "Congratulations to the Wendelstein 7-X team on the new world record," said Germany's Federal Research Minister "The approach is the right one – in this way important new findings have been made for the future use of fusion power stations fusion energy could be the energy source of the future The researchers in Greifswald have taken an important step in this direction with their work I wish the team every success with their future work." Though more than a million assembly hours went into the initial construction of the Wendelstein 7-X the stellarator remains a constant work in progress the interior walls of the container were fitted with graphite tiles allowing for higher internal temperatures and longer plasma discharges Though these proved pivotal in the team's latest success they are already due to be replaced with water-cooled elements made from carbon fiber This will help the team work toward its aims of continuously containing super-hot plasma in the Wendelstein 7-X's contorted magnetic fields for more than 30 minutes at a time Though the device is not actually designed to produce energy this highly elaborate proof-of-concept device would provide compelling evidence that stellarators can form part of an environmentally sustainable energy mix Source: Max Planck Institute for Plasma Physics Metrics details An Erratum to this article was published on 14 February 2017 Fusion energy research has in the past 40 years focused primarily on the tokamak concept but recent advances in plasma theory and computational power have led to renewed interest in stellarators The largest and most sophisticated stellarator in the world with the aim to show that the earlier weaknesses of this concept have been addressed successfully and that the intrinsic advantages of the concept persist also at plasma parameters approaching those of a future fusion power plant obtained before plasma operation: that the carefully tailored topology of nested magnetic surfaces needed for good confinement is realized and that the measured deviations are smaller than one part in 100,000 This is a significant step forward in stellarator research since it shows that the complicated and delicate magnetic topology can be created and verified with the required accuracy which for a typical operating point in magnetic fusion reactor studies is a few seconds A promising approach to meeting this challenge is the use of a magnetic field that creates toroidal magnetic surfaces Some representative nested magnetic surfaces are shown in different colours in this computer-aided design (CAD) rendering together with a magnetic field line that lies on the green surface The coil sets that create the magnetic surfaces are also shown allowing for a view of the nested surfaces (left) and a Poincaré section of the shown surfaces (right) Four out of the five external trim coils are shown in yellow would appear at the front of the rendering a strong toroidal current driven within the plasma is needed to generate the poloidal magnetic-field component The stellarator’s lack of a strong current parallel to the magnetic field greatly reduces macroscopic plasma instabilities and it eliminates the need for steady-state current drive These are important advantages for a power plant The stellarator was invented by Lyman Spitzer in the 1950s (ref. 3) And why do some believe that it is about to have a comeback Plasma confinement in early stellarators was disappointing This was due to poorly confined particle orbits—many of the particle trajectories were not fully confined If each guiding centre (the point around which the particle performs its rapid gyration) were to stay exactly on the magnetic field line it starts out on the magnetic surfaces would guarantee good confinement since the guiding centres drift perpendicular to the magnetic field This is due to the field-line curvature and magnetic field strength inhomogeneities inherent to the toroidal magnetic topology the drift is on the order of 10,000 times slower than the particle velocity it will lead to particle losses in less than 1/10 of a second if the drifts do not average out or stay within the magnetic surface but instead carry the particle from the inner to the outer magnetic surfaces This was the case in early stellarator experiments The tokamak and the reversed-field pinch do not suffer from this problem since their toroidal symmetry makes the particle drifts average out for all the particles and therefore only cause minor excursions from the magnetic surface Strict requirements for the manufacturing and assembly accuracy of the coils add to the engineering challenge which was in fact viewed by some as unrealistic High engineering accuracy is needed because small magnetic field errors can have a large effect on the magnetic surfaces and the confinement of the plasma The measurements that are presented in the following sections confirm that the engineering challenges of building and assembling the device A magnetic surface is not only characterized by its shape and enclosed volume This is a measure of the poloidal rotation (‘twist’) of the field lines as one follows them around the magnetic surface; ɩ=1/2 indicates that the field line moves halfway around a magnetic surfaces in the poloidal direction for each toroidal turn it makes the field line bites itself in the tail after two toroidal transits Since there are many more irrational than rational numbers and a magnetic field line generally does not close on itself it densely traces out a two-dimensional surface The field lines making up a magnetic surface are visualized in a dilute neutral gas in this case primarily water vapour and nitrogen (pn≈10−6 mbar) The three bright light spots are overexposed point-like light sources used to calibrate the camera viewing geometry The Poincaré section of a closed magnetic surface is measured using the fluorescent rod technique The electron beam circulates more than 40 times island chains with a detectable and operation-relevant size only appear for low-order rational values of ɩ and only if there is a Fourier component of the magnetic field that has matching (that is resonant) toroidal and poloidal mode numbers For the symmetry-breaking n=1 through 4 error fields deformations due to electromagnetic forces do not play a major role and the bmn’s are largely independent of the magnitude of B0 in contrast to the effects discussed in the ‘Discussion’ section Of particular concern is the n=1 component which would create an n/m=1/1 island chain The width of an island chain depends on the square root of the resonant field component as well as the poloidal mode number m and the size of the device (via the major radius R0=5.5 m in W7-X) the rotational transfrom ɩ is nearly constant from the inner to the outer magnetic surfaces and a sizeable island chain will result from even a very small resonant error field ɩ can be determined at a specific radial location We show in the following that effects due to slight deformations of the magnetic coils are clearly visible and that an important error field component in W7-X has been measured to be less than 1 in 100,000 both in terms of the as-built engineering of a fusion device as well as in the measurement of magnetic topology The magnetic topology used for initial plasma experiments in W7-X was chosen so as to avoid island chains at the plasma edge29 The rotational transform ɩ varies from 0.79 in the centre to 0.87 at the outer magnetic surface that just touches the graphite limiters installed to protect in-vessel components by intercepting the plasma heat loads The 5/6 island chain is visible in a poloidal-radial Poincaré plot created by an electron gun and a sweep rod, as a set of six ‘bubbles’, reflecting the m=6 poloidal mode number. A thin background gas in the chamber creates a visualization of the field lines that create the x-points of the island chain. The 5/6 island chain is shown in cyan for B=0.4 T Although nominally one might expect them to be identical the 5/6 island chain is about 10 cm further out at high field strength due to small deformations of the magnet coils under electromagnetic forces The ɩ profile is shown for the special configuration developed for field error detection The ɩ varies only minimally around the resonant value of 1/2 The x axis is a measure of the minor radial size (in meters) of the magnetic flux surface m=10 island chain would appear at the ɩ=1/2 location at around 25 cm distance from the innermost magnetic surface but in the presence of even a small n=1 error field visible in a Poincaré plot as two ‘bubbles’ The B21 error field is too small to create an island structure large enough to be measured clearly This is in part due to the good news that it is small and in part due to ɩ being so close to 1/2 that the electron beam comes very close to its launch position (the electron gun) after two toroidal transits thus running the risk of hitting the back of the electron gun and disappearing The primary purpose of these coils is to trim away the unwanted n=1 error field components but the trim coils are used here to create an extra n=1 error field and thus generate an n/m=1/2 island chain wide enough to be measurable Light fibres installed in the vessel along with detailed measurements of their location allow the pixels of the image plane to be mapped to physical dimensions the width of the island in physical units can be inferred from a measurement in pixels Error bars account for both the physical width of the flux surface traces and the step size going from outside the island chain to inside it A best attempt is made to report the maximum width of the magnetic islands By scanning the phase and amplitude of the imposed, well-defined error field, measuring the island phase and width (Fig. 7), and comparing with equation 1, we find that an n/m=1/2 island with a width of 4 cm must be present, even in the absence of trim-coil induced fields. m=2 island size and phase can be measured by the Poincaré section method Here two conglomerate images a and b with several nested surfaces are shown for two different phases of a purposely added n=1 field structure with the same amplitude Although the shadowing problem leads to gaps the trained eye can still detect the changes in size and phase of the m=2 island The measured island widths are compared directly with those predicted from numerical calculations that take the as-built as-installed geometry of the W7-X coil set into account The offset from zero in the linear fits indicate the intrinsic 4 cm island width the points would have lined up with the dotted lines The island widths are determined from the real or synthetic images by use of an image processing software programme developed for these purposes Since it was not always possible to image the edge of the island chain exactly the electron beam gives a certain width to an island chain or a magnetic surface The error bars indicate the largest and smallest possible island size consistent with the data Since the B11 and the B21 components should be roughly of the same order of magnitude and since the B21 error is reproduced by our numerical models the b11 error is also expected to be small likely close to or somewhat below the aforementioned estimate of 1.1 × 10−4 thus well within the correction capabilities of the W7-X coil set The need for complex 3D shaping and high-accuracy requirements have been viewed as major problems for optimized stellarators superconducting stellarator can be built with an accuracy sufficient to generate good magnetic surfaces with the required topology and that experimental tools exist to verify the magnetic topology down to and below errors as small as 1:100,000 These results were obtained using magnetic field-line mapping a sensitive technique to measure the detailed topology of the magnetic surfaces and provide an answer to the question ‘is the stellarator the right concept for fusion energy?’ years of plasma physics research is needed The data sets generated and/or analysed during the current study are available from the corresponding author on reasonable request Confirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000 Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations A correction has been published and is appended to both the HTML and PDF versions of this paper Self-organized helical equilibria as a new paradigm for ohmically heated fusion plasmas Quasi-helically symmetric toroidal stellarators Plasma equilibrium with rational magnetic surfaces Experimental demonstration of improved neoclassical transport with quasihelical symmetry Major results from the stellarator Wendelstein 7-AS Physics and engineering design for Wendelstein VII-X Stable stellarators with medium β and aspect ratio Technical challenges in the construction of the steady-state stellarator Wendelstein 7-X The influence of errors on the plasma confining magnetic field On conservation of conditionally periodic motions for a small change in Hamilton’s function Small denominators and problems of stability of motion in classical and celestial mechanics On Invariant Curves of Area-Preserving Mappings of an Annulus Non-axisymmetric magnetic fields and toroidal plasma confinement Magnetic surface visualizations in the Columbia Non-Neutral Torus Three-dimensional photogrammetric measurement of magnetic field lines in the WEGA stellarator Magnetic surface mappings by storage of phase-stabilized low-energy electron beams A new method for studying the vacuum magnetic configuration in stellarators Magnetic surface mapping with highly transparent screens on the Auburn torsatron Detailed investigation of the vacuum magnetic surfaces on the W7-AS stellarator Physical Aspects and Design of the Wendelstein 7-X Divertor The superconducting magnet system of the stellarator Wendelstein 7-X Influence of construction errors on Wendelstein 7-X magnetic configurations Tracking of the magnet system geometry during Wendelstein 7-X construction to achieve the designed magnetic field Magnetic surfaces and containment of a plasma by spiral fields in a stellarator with external injection Electron beam and magnetic field mapping techniques used to determine field errors in the ATF torsatron Plans for the first plasma operation of Wendelstein 7-X Setup and initial results from the magnetic flux surface diagnostics at Wendelstein 7-X First measurements of error fields on W7-X using flux surface mapping The trim coils for the Wendelstein 7-X magnet system Methods for measuring 1/1 error field in Wendelstein 7-X stellarator Download references This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement No 633053 acknowledges support from US DOE grant DE-AC02-09CH11466 Søndergaard Larsen for useful suggestions to improve the text A full list of consortium members appears at the end of the paper George Hutch Neilson & Novimir Pablant Boudewijn van Milligen & Jose-Luis Velasco Max Planck Institute for Solar System Research Instytut Fizyki Plazmy I Laserowej Mikrosyntezy Lionello Marrelli & Maria Ester Puiatti Stefan Schmuck & Christian Perez von Thun Yaroslav Kolesnichenko & Vadym Lutsenko Ecole Royale Militaire—Koninklijke Militaire School led the design and construction of the flux surface measurement system conducted the flux surface measurement experiments The article was written primarily by T.S.P. The W7-X team contributed the infrastructure the metrology measurements and proper operation of W7-X the cryostat and the superconducting magnet system The authors declare no competing financial interests Download citation The Wendelstein 7-X - the world's largest stellarator-type fusion device - started scientific operation yesterday with the production of its first hydrogen plasma Since the start of its operation on 10 December the Wendelstein 7-X device at the Max Planck Institute for Plasma Physics (IPP) in Greifswald has produced more than 300 plasmas using helium These served primarily to clean the plasma vessel allowing the plasma temperature to increase The first plasma in the machine had a duration of one-tenth of a second and achieved a temperature of around one million degrees Celsius a plasma temperature of six million degrees Celsius was achieved German Chancellor Angela Merkel pressed a button to initiate the first hydrogen plasma in Wendelstein 7-X A 2MWt pulse of microwave heating transformed a tiny quantity of hydrogen gas into an extremely hot low-density hydrogen plasma This entailed separating the electrons from the nuclei of the hydrogen atoms head of the division responsible for operation of Wendelstein 7-X said: "With a temperature of 80 million degrees and a lifetime of a quarter of a second the device's first hydrogen plasma has completely lived up to our expectations." A statement from the IPP said the current initial experimentation phase will last until mid-March after which the plasma vessel will be opened in order to install carbon tiles to protect the vessel walls and a so-called "divertor" for removing impurities "These facilities will enable us to attain higher heating powers and longer discharges lasting up to 10 seconds," explained Thomas Klinger discharges lasting 30 minutes can be produced and it can be checked at the full heating power of 20MWt whether Wendelstein 7-X will achieve its optimisation targets Wendelstein is a stellarator fusion reactor - different to a tokamak fusion reactor such as the Joint European Torus in the UK or the Iter device under construction in France A tokamak is based on a uniform toroid shape whereas a stellarator twists that shape in a figure-8 This gets around the problems tokamaks face when magnetic coils confining the plasma are necessarily less dense on the outside of the toroidal ring The Wendelstein 7-X will not be used to produce energy but should demonstrate whether stellarators are suitable as a power plant It should show that stellarators - with discharges lasting 30 minutes - have the ability to operate continuously tokomaks can only operate in pulses without auxiliary equipment Some €370 million ($408 million) has been invested in the Wendelstein 7-X project with funding from federal and state governments and the European Union Researched and writtenby World Nuclear News Metrics details An Author Correction to this article was published on 11 September 2018 A Publisher Correction to this article was published on 03 July 2018 The two leading concepts for confining high-temperature fusion plasmas are the tokamak and the stellarator Tokamaks are rotationally symmetric and use a large plasma current to achieve confinement whereas stellarators are non-axisymmetric and employ three-dimensionally shaped magnetic field coils to twist the field and confine the plasma the magnetic field of a stellarator needs to be carefully designed to minimize the collisional transport arising from poorly confined particle orbits which would otherwise cause excessive power losses at high plasma temperatures this type of transport leads to the appearance of a net toroidal plasma current we analyse results from the first experimental campaign of the Wendelstein 7-X stellarator showing that its magnetic-field design allows good control of bootstrap currents and collisional transport The energy confinement time is among the best ever achieved in stellarators both in absolute figures (τE > 100 ms) and relative to the stellarator confinement scaling The bootstrap current responds as predicted to changes in the magnetic mirror ratio These initial experiments confirm several theoretically predicted properties of Wendelstein 7-X plasmas and already indicate consistency with optimization measures Prices may be subject to local taxes which are calculated during checkout In the version of this Article originally published and in the associated Publisher Correction the members of the W7-X Team were not included have now been amended to include these team members Mollén’s affiliation was incorrectly denoted as number 10; it should have been 1 some technical problems in typesetting meant that the tilde symbol above b and one instance of a superscript 2 were too high to be visible; see the correction notice for details 35 on page one of the Supplementary Information was incorrect; it should have been to ref Stellarator and tokamak plasmas: a comparison Ripple transport in helical-axis advanced stellarators: a comparison with classical stellarators/torsatrons Core electron-root confinement (CERC) in helical plasmas Some considerations on closed configurations of magnetohydrostatic equilibrium Development of quasi-isodynamic stellarators Diffusion-electrical phenomena in a plasma confined in a tokamak machine Diffusion driven plasma currents and bootstrap tokamak Bootstrap-current experiments in a toroidal plasma-confinement device Bootstrap current and neoclassical transport in quasi-isodynamic stellarators Effect of error field correction coils on W7-X limiter loads Performance and properties of the first plasmas of Wendelstein 7-X Major results from the first plasma campaign of the Wendelstein 7-X stellarator Key results from the first plasma operation phase and outlook for future performance in Wendelstein 7-X Wendelstein 7-X program—Demonstration of a stellarator option for fusion energy Limiter observations during W7-X first plasmas Characterization of energy confinement in net-current free plasmas using the extended International Stellarator Database Energy confinement scaling from the International Stellarator Database Physics model assessment of the energy confinement time scaling in stellarators Confinement in Wendelstein 7-X limiter plasmas Chapter 2: Plasma confinement and transport Neoclassical transport simulations for stellarators commissioning and start of the Wendelstein 7-X stellarator operation First results from protective ECRH diagnostics for Wendelstein 7-X Inference of the microwave absorption coefficient from stray radiation measurements in Wendelstein 7-X Wall conditioning by ECRH discharges and He-GDC in the limiter phase of Wendelstein 7-X Benchmarking of the mono-energetic transport coefficients—results from the International Collaboration on Neoclassical Transport in Stellarators (ICNTS) Three-dimensional free boundary calculations using a spectral Green's function method Service oriented architecture for scientific analysis at W7-X Plasma transport coefficients for nonsymmetric toroidal confinement systems Variational bounds for transport coefficients in three‐dimensional toroidal plasmas Comparison of particle trajectories and collision operators for collisional transport in nonaxisymmetric plasmas 3D edge modeling and island divertor physics Numerical investigation of plasma edge transport and limiter heat fluxes in Wendelstein 7-X startup plasmas with EMC3-EIRENE Overview of diagnostic performance and results for the first operation phase in Wendelstein 7-X Engineering design for the magnetic diagnostics of Wendelstein 7-X Core radial electric field and transport in Wendelstein 7-X plasmas Investigation of turbulence rotation in limiter plasmas at W7-X with a new installed poloidal correlation reflectometry Electron cyclotron resonance heating and current drive in the W7-X stellarator Download references This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement 633053 This work is partially supported by the US Department of Energy under a project agreement with the Max Planck Institute for Plasma Physics A full list of authors and affiliations appear at the end of the paper Laboratory for Plasma Physics of the Ecole Royale Militaire/Koninklijke Militaire School (LPP-ERM/KMS) National Centre for Nuclear Reserach Świerk Brandenburg University of Technology Cottbus-Senftenberg Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie Fraunhofer-Institut für Schicht- und Oberflächentechnik IST Institute of Applied Physics of the Russian Academy of Science Institute of Plasma Physics of the Czech Academy of Science Instituto di Fisica del Plasma ‘Piero Caldirola’ Fraunhofer-Institut für Werkzeugmaschinen und Umformtechnik IWU prepared the configuration changes and the discharge program Supplementary notes, supplementary figures 1–2, supplementary tables 1–2 Download citation DOI: https://doi.org/10.1038/s41567-018-0141-9 The installation of water-cooled inner cladding of the plasma vessel will make the facility suitable for higher heating power and longer plasma pulses Production of the new cladding's centrepiece was taken over by the institute's Garching branch The divertor is the most heavily loaded component of the plasma vessel In 10 double strips on the inner wall of the plasma vessel the divertor tiles follow the curved contour of the plasma edge They protect those wall areas to which particles from the edge of the plasma are magnetically directed A pump behind a gap in the middle of each double strip removes the impinging plasma and impurity particles the divertor can be used to control the purity and density of the plasma the experiments on Wendelstein 7-X - at the Max Planck Institute for Plasma Physics in Greifswald - were temporarily terminated after two successful work phases Upgrading of the plasma vessel has been ongoing since then most of the old components had to be taken out Installation of the new ones can now begin," said Hans-Stephan Bosch whose division is responsible for technical operation of the device Whereas most of the wall protection components were previously operated uncooled large sections of the wall will be water-cooled starting with the next round of experiments "This will then enable Wendelstein 7-X to generate plasma pulses lasting up to 30 minutes," Bosch said In the high-performance experiments planned are designed to withstand a load of up to 10 megawatts per square metre the heat-resistant divertor tiles (made of carbon-fibre-reinforced carbon) would not be able to withstand this load for the intended 30-minute plasma pulses They are therefore welded onto water-cooled plates made of a copper-chromium-zirconium alloy Plasma operation is expected to resume at the end of 2021 It is planned to begin with low water cooling low heating power and short plasma pulses in order to allow testing of all installations in operation after the long break in experiments longer pulses with plasma energies of up to one gigajoule should be possible - a target that will be slowly approached Instead of the previous hundred-second pulses with heating powers of two megawatts and plasma energies of 200 megajoules the cooled high-performance divertor should later allow pulses lasting up to 30 minutes at full heating power This gets round the problems tokamaks face when magnetic coils confining the plasma are necessarily less dense on the outside of the toroidal ring It should show that stellarators have the ability to operate continuously Fusion systems of the stellarator type promise high-performance plasmas in continuous operation heat and particles from the hot plasma permanently stress the vessel walls It is the task of the divertor – a system of specially equipped baffle plates to which the particles from the edge of the plasma are magnetically directed – to regulate the interaction between plasma and wall Wendelstein 7-X is being used to investigate the suitability of such devices for power plants experiments on Wendelstein 7-X were halted temporarily after two successful phases Upgrading of the plasma vessel has been continuing since then Installation of the new ones can now begin,” said Hans-Stephan Bosch “Whereas most of the wall protection components were previously operated uncooled This will then enable Wendelstein 7-X to generate plasma pulses lasting up to 30 minutes,” Mr Bosch said The aim of fusion research is to develop an environmentally sound and climate-friendly power plant it will generate energy from the fusion of atomic nuclei Because the fusion fire only ignites at temperatures above 100 million degrees the fuel – a low-density hydrogen plasma – must not come into contact with the cold vessel walls it floats almost contact-free inside a vacuum chamber The Wendelstein 7-X stellarator is intended to investigate the suitability of this type of device for a power plant Stellerator devices and tokamak-type fusion units like the International Thermonuclear Experimental Reactor under construction in France are both types of toroidal (doughnut-shaped) magnetic confinement devices In order for the plasma to have good confinement in the doughnut-shaped chamber a large current flows in the plasma to generate the required twisted path the large current can drive "kink" instabilities which can cause the plasma to become disrupted the twist in the magnetic field is obtained by twisting the entire machine itself and makes the plasma intrinsically more stable The cost comes in the engineering complexity of the field coils and reduced confinement meaning the plasma is less easily contained within the magnetic bubble While the Wendelstein 7-X and Iter use different approaches most of the underlying technology is identical They are both toroidal superconducting machines and both use external heating systems such as radio frequency and neutral beam injection to heat the plasma and much of the plasma diagnostic technology is in common On 10 December 2015 the first helium plasma was produced in the Wendelstein 7-X fusion device at the Max Planck Institute for Plasma Physics (IPP) in Greifswald experimental operation has now commenced according to plan Wendelstein 7-X is the world's largest stellarator-type fusion device The Wendelstein 7-X stellarator is an experimental nuclear fusion reactor designed to bring us closer to the prospect of clean, limitless energy, and since producing its first plasma in 2015 we've seen it take steady and significant steps toward that aim Physicists have just confirmed another "major advance" that could see the reactor host plasma twice as hot as the Sun's core as a result of efforts to address inherent energy losses in the design Stellarators stand apart from the more common, symmetrical doughnut-shaped tokamak fusion reactors as hugely complex structures full of twists and turns. As it is with all nuclear fusion reactors the goal is to recreate the processes at play within the Sun by subjecting streams of plasma to extreme temperature and pressure forcing atoms to collide and fuse together to produce monumental amounts of energy The Wendelstein 7-X reactor is so complex it required supercomputers to design. It uses a series of 50 superconductive magnetic coils to hold in place plasma as it loops around a twisting and turning circular chamber. In 2018, physicists working on the project set new records for energy density and plasma confinement for a fusion reactor of this type These experiments also saw the plasma heated to temperatures of 20 million °C (36 million °F) comfortably exceeding the Sun's temperature of 15 million °C ( 27 million °F) But it turns out the Wendelstein 7-X might be destined for far higher temperatures than that engineers set out to address one limitation that plagues classic stellarator designs far more than tokamaks a type of heat loss known as "neoclassical transport." This occurs as collisions between the heated particles knock some out of their orbit and cause them to drift outward from the magnetic field The magnetic field cage of the Wendelstein 7-X was very carefully optimized to prevent these types of losses To determine whether that careful planning has paid off scientists from the Max Planck Institute for Plasma Physics and Princeton Plasma Physics Laboratory (PPPL) have carried out detailed new analysis of the stellarator's round of record-breaking experiments This analysis focused on diagnostic data collected by X-ray imaging crystal spectrometer and showed a sharp reduction in neoclassical transport and revealed that the high temperatures could not have been achieved otherwise “This showed that the optimized shape of W7-X reduced the neoclassical transport and was necessary for the performance seen in W7-X experiments,” says PPPL physicist Novimir Pablant “It was a way of showing how important the optimization was.” This performance was achieved with what's described as currently available "modest heating power," and the analysis shows that the Wendelstein 7-X is capable of confining heat that reaches temperatures twice as high as those found in the Sun's core in the future But as the team pursues nuclear fusion there are many balls to juggle other than hitting high temperatures including addressing other forms of heat loss and will involve a new water-cooling system design to allow for lengthier experiments “It’s really exciting news for fusion that this design has been successful,” says Pablant “It clearly shows that this kind of optimization can be done.” A paper describing the research was published in the journal Nature.  Source: PPPL Company is spin-out from Max Planck Institute for Plasma Physics a spinoff of the Max Planck Institute for Plasma Physics in Germany has raised €20m ($21.7m) in seed funding to build the first generation of fusion power plants based on quasi-isodynamic (QI) stellarators with high-temperature superconductors The Munich-based company said the seed round led by Swiss venture capital firm redalpine with participation from the Bavarian government-backed Bayern Kapital German government-backed DeepTech & Climate Fonds and the Tomorrow fund have doubled down on their pre-seed investments A stellarator is a doughnut-shaped ring of precisely positioned magnets that can contain the plasma from which fusion energy is born Proxima Fusion said QI stellarators hold promise for a carbon-free safe and effectively limitless source of energy The science behind this class of magnetic confinement fusion devices has been the subject of research for more than six decades achieving sustained and commercially viable fusion remains a challenge stellarator optimisation results entirely disrupted the field enabling Proxima Fusion to tackle these challenges with an engineering- and simulation-focused approach The company said it is building on groundbreaking results from the Wendelstein 7-X (W7-X) experiment the world’s largest stellarator at the Max Planck Institute for Plasma Physics Those results follow €1.3bn of “visionary” public investment by the German government and the European Union one of the world's leading plasma research laboratories just broke a world record with the Wendelstein 7-X which has exceeded all expectations One of the greatest challenges of our time is to find a way to power our activity on Earth with sustainable and clean energy sources Fusion is one of the most promising solutions that could satisfy humanity's need for electrical energy for the centuries to come The experimental stellerator Wendelstein 7-X led by the Max Planck Institute for Plasma Physics (IPP) aims to demonstrate the suitability of such a device as a future power plant the main challenge in its development is that the fusion reaction requires a heating system capable of raising the plasma's temperature to 100 million degrees Celsius the W7-X experiment needs highly efficient microwave gyrotrons which are capable of generating 1MW of full power The next generation of gyrotrons is leading the experiment into a technological tour de force and this process is being pushed forward by the close cooperation between Thales Microwave & Imaging Sub-Systems and the Karlsruhe Institute of Technology (KIT) Record results in plasma heating experiments One of the world's leading plasma research laboratories just broke a new record reaching temperatures 4 times hotter than before Equipped with Thales Microwave & Imaging Sub-Systems gyrotrons the W7-X reached 40 million degrees Celsius over several seconds pushing 18 times more than the last achievement A recent article in the online journal Nature Communications confirms that the complex topology of the magnetic field of Wendelstein 7-X—the world's largest stellarator—is highly accurate with deviations from design configuration measured at fewer than 1-in-100,000 high engineering accuracy is needed because even the smallest magnetic field errors can have a large effect on the magnetic surfaces and the confinement of the plasma A German startup has secured its first investment to scale a bizarre twisted-looking fusion machine that could power the world with abundant Proxima Fusion raised €‎7mn in funding to build a device known as a stellarator, a little-known fusion reactor that could hold the key to unlocking the potential of atom-fusing power within our lifetime it is noteworthy because the startup is the first spinout from Germany’s esteemed Max Planck Institute for Plasma Physics The institute is solely dedicated to fusion research and is home to the world’s largest stellarator the machine is the result of 27 years of research and design (and €‎1.3bn of investment) aided by recent advancements in supercomputing and state-of-the-art plasma theory While the physics behind the machine is extremely complicated what matters is that stellarators offer a number of potential advantages to the more popular doughnut-shaped tokamak — a design that has dominated the fusion sector for decades The twisted configuration of the superconducting magnets in a stellarator help to keep the super-heated plasma they contain stable enough to fuse nuclei and release energy Even more crucial for a future fusion power plant they can theoretically operate continuously whereas tokamaks must stop periodically to reset their magnet coils stellarators are notoriously complex to design and build which is why they were largely set aside in the 1960s in favour of their simpler cousin “A tokamak is kind of easy to design, hard to operate, whereas a stellarator is super hard to design but once you’ve designed it, it’s way easier to operate,” Ian Hogarth, co-founder of Plural Platform, which is leading the €7mn investment, told the Financial Times it has achieved a number of scientific breakthroughs that are “basically defining the whole field of magnetic confinement fusion,” said Hogarth Fusion physicist Josefine Proll of the Eindhoven University of Technology is equally excited. “All of a sudden, stellarators are back in the game,” she said looks to take these developments commercial Its CEO Francesco Sciortino believes that the startup’s connection to the Max Planck Institute which has more people working on plasma physics than MIT and really make this a European champion?” he asked While private investment has poured into tokamak pioneers — such as the likes of MIT spinout CFS, valued at over $2bn — recent breakthroughs in stellarator technology could pave the way for a new cohort of fusion startups like Proxima Type One, a spinoff from the University of Wisconsin-Madison, and Proxima’s only other competitor so far, raised $29mn in March from Bill Gates’ Breakthrough Ventures to develop a commercially viable stellarator While the stellarator startup scene is powering up director of the Max Planck Institute’s Greifswald branch cautioned that commercially viable operations could still be 25 years away if the technology can deliver on the promise of limitless clean energy — then it’s probably worth the wait would really like to nerd out on stellarator technology a bit more check out this fascinating explainer from the Max Planck Institute: Get the most important tech news in your inbox each week Delivery of the last major components for the Wendelstein 7-X fusion device now being built at the Greifswald branch of Max Planck Institute for Plasma Physics (IPP) marks completion of the industrial manufacture of the main elements The last two sections of the outer casing are at IPP in Greifswald Assembly of the large-scale experiment is now in full swing Click here to read more... Testing of the Wendelstein 7-x stellarator has started with a bang with researchers switching on the experimental fusion reactor to produce its first helium plasma at the Max Planck Institute for Plasma Physics (IPP) in Greifswald After almost a decade of construction work and more than a million assembly hours the first tests have gone according to plan with the researchers to shift focus to producing hydrogen plasma after the new year Assembly of the Wendelstein 7-x stellarator was completed in April of last year and after a period of careful testing of its various components the science team finally flicked the switch on December 10 This saw around a single milligram of helium gas heated to one million degrees Celsius (1.8 million° F) with the flash observed on cameras and measuring devices for one tenth of a second As part of the ongoing pursuit of a clean and reliable power source, the Wendelstein 7-x is the largest stellarator fusion device in the world and represents a different approach to typical doughnut-shaped tokamak fusion reactors Scientists hope that the stellarator design can overcome one of the main limitations of the tokamak where the plasma contained in the vessel is prone to drifting into the outer walls and collapsing after operating only in short bursts The designers of the Wendelstein 7-x are of the view that the device will offer the required stability for continuous nuclear fusion power generation It uses a cage of 50 superconducting coils to suspend super-hot plasma in the center of a twisting magnetic field for more than 30 minutes at a time the team will now aim to prolong the duration of the plasma discharges and explore the best means of producing and heating helium plasma using microwaves the team will then turn its attention to producing the first plasma from hydrogen You can see the fleeting flash of helium plasma and the reactions of control team in the video below Source: Max Planck Institute for Plasma Physics In a large complex located at Greifswald in the north-east corner of Germany sits a new and unusual nuclear fusion reactor awaiting a few final tests before being powered-up for the very first time Dubbed the Wendelstein 7-x fusion stellarator it has been more than 15 years in the making and is claimed to be so magnetically efficient that it will be able to continuously contain super-hot plasma in its enormous magnetic field for more than 30 minutes at a time this new reactor may help realize the long-held goal of continuous operation essential for the success of nuclear fusion power generation the quirky stellarator design aims to provide an inherently more stable environment for plasma and a more promising route for nuclear fusion research in general Initially an American design conceived by Lyman Spitzer working at Princeton University in 1951 the stellarator was deemed too complex for the constraints of materials available in the middle of the 20th Century and the more easily constructed toroid of the tokamak won out as the standard model for fusion research Though some stellarators have been constructed over the course of time – notably the predecessor to this latest iteration known as the Wendelstein 7-AS (Advanced Stellarator) – the calculations required to ensure ultimate plasma containment and control have only become possible with the advent of supercomputers algorithms specifically created to fuse theory and practice have now been applied to the design of the Wendelstein 7-x and its designers firmly believe that this latest version will have the stability required to be the precursor machine to full-blown continuous nuclear fusion power generation For the eventual success of nuclear fusion power (essentially where two isotopes of hydrogen are subject to such energy that the strong nuclear force is overcome and they fuse to form helium and release copious amounts of neutron energy) This is because the enormous pressures and temperatures (around 100 million degrees Celsius (180 million °F)) used to create the plasma and then accelerate the resulting ion and electron soup around the containment vessel means that any instability in the magnetic containment field or the pressure vessel itself will result in degradation and ultimately the failure of the process the stellarator eschews the method of inducing current through the plasma to drive electrons and ions around the inside of the vessel as found in tokamak designs instead relying entirely on external magnetic fields to move the particles along stellarator designs are basically immune to the sudden and unexpected disruptions of plasma and the enormous – and often destructive – magnetic field collapses that sometimes occur in tokamaks a stellarator reactor is able to hold the plasma in a containment field that twists through a set of magnetic coils to continuously hold the plasma away from the walls of the device with its doughnut-shaped containment vessel and electromagnet windings that loop through the center of the toroid and around the outside the magnetic field is stronger in the center than it is on the outer side This means that plasma contained in a tokamak tends to drift to the outer walls where it then collapses avoids this situation by twisting the entire containment vessel into a shape that constantly forces the plasma stream into the center of the reactor vessel as it continuously encounters magnetic fields in opposing positions along its entire length The advantages of the stellarator over the tokamak come at a cost as the many twists and turns that give the stellarator an advantage in magnetic containment also mean that many particles can simply be lost as they veer off course following the path of the containment vessel itself a great many more magnetic coils are required for the stellarator and must be set up at very close intervals around the structure and super-cooled with liquid helium for maximum efficiency 3.5-meter-tall (11.5-ft) non-planar super-conducting electromagnets alone is around 425 tonnes (468 tons) and their placement makes construction difficult and their assembly fraught with problems Not to mention the fact that piping around vast quantities of liquid helium to ensure that the electromagnets superconduct at temperatures close to absolute zero makes the Wendelstein 7-x a plumber's nightmare and a tricky addition to an already difficult balancing act the physical design of the stellarator itself requires access ports for fuel ingress and egress along with a myriad other entry points for instruments and all the other necessary paraphernalia necessary to monitor the enormous pressures and temperatures that it will be subject to in operation tests on the completed stellarator to maintain the sub-millimeter accuracy for the plasma path are progressing and show promise an electron beam was injected into the stellarator and progressed along a predetermined field line in the circular tracks through the evacuated plasma vessel the beam created a tracer in its wake created by collisions with electrons contained in the residual gas in the vessel as the electron beam constantly circulated through the system a fluorescent rod was pushed transversely through the vessel in cross section visible spots of light were created and the results recorded with a camera the whole cross section of the magnetic field was gradually made visible "Once the flux surface diagnostics were placed in operation we were immediately able to see the first magnetic surfaces," said Dr the man responsible for this measurement process "Our images clearly show how magnetic field lines create closed surfaces in many toroidal circulations." claim to be "close" to producing a working This is where IPP's proving of the technology over the coming months leading to a full-blown commissioning of the machine may well provide the nexus between theory and practicality and if not deliver on the promise of boundless energy at least provide a proof of concept and renew flagging interest in a field that may With approval to continue from nuclear regulators in Germany expected by the end of this month the Wendelstein 7-x stellarator is slated for its first fully-operational tests in November this year At a cost of more than €1 billion ($US 1.1 billion) and over one million man-hours of work committed so far the hopes of Europe's future being a nuclear fusion-powered one may well rest on the ability of this machine to perform as expected Source: IPP The breakthrough design of the fusion reactor was only possible using extremely powerful computers known as supercomputers But that's just the outcome of a very systemic physics and engineering process that is behind it,’ explained project leader Professor Thomas Klinger of the Max-Planck-Institute for Plasma Physics in Germany.  The strange-looking layout of the Wendelstein 7-X created with the help of EU research funds is a result of the unique needs of its stellarator design so-named because it mimics the conditions taking place inside stars where huge amounts of energy are released by fusing hydrogen into helium clean energy if attempts to build a fully operational reactor are successful. However it is only possible at incredibly high temperatures where electrons are stripped from hydrogen atoms to create ionised plasma Such plasma must be kept hot enough for fusion to occur and material walls would cool it down which is why scientists must trap the plasma using powerful magnets.  ‘The magnetic field coils have to have just the shape to create the right magnetic field,’ Prof ‘We have been doing a long research phase of 20 years in which it was found out what the actual field is we need Those requirements led to the Wendelstein device created a uniquely shaped superconducting magnet system to hold the plasma That is then surrounded by an outer vessel to keep the coils cool in a vacuum at -270 degrees Celsius with liquid helium Keeping the plasma confined is the number one challenge faced by scientists the project began testing the system with hydrogen plasma for the first time ‘The first hydrogen plasma had a duration of 40 milliseconds and we were able to create hydrogen plasma more recently for 8 seconds So that’s an increase by a factor of 200,’ Prof the team hopes to be running the stellarator at full power for ten seconds after installing more graphite elements for the wall they plan to introduce active water cooling which they hope will enable them to run the device for 30 minutes The wild design of the stellarator is crucial to giving scientists the greatest flexibility to try out different magnetic fields to see how the plasma behaves and if the confinement is getting better.The IssueGlobal warming will cause sea levels to rise 3.2 centimetres by the year 2025, and possibly 0.82 metres by the end of the century, according to projections compiled by the UN’s Intergovernmental Panel on Climate Change To prevent catastrophic sea level rises and stop the world warming by over 2 degrees Celsius compared with pre-industrial levels EU and world leaders agreed during the COP21 conference in Paris to rein in greenhouse gas emissions If it can be made to work cost-effectively, nuclear fusion has the potential to dramatically reduce CO2 emissions in Europe, which were estimated at 4 611 million tonnes in 2013.  and we can control each current circuit to run the coil separately seven knobs to turn … with which we create different magnetic field configurations,’ Prof Trying to find the best confining and heat insulating field is one of the main scientific tasks of the experimental device but the complex behaviour of the trapped plasma makes that difficult.  The trick of the Wendelstein’s stellarator design is that the external magnetic coils twist the entire magnetic field itself to counteract against unwanted drift motions.  In the south of France, researchers at the ITER project are testing an alternative, doughnut-shaped fusion reactor design where a strong electric current in the plasma is ramped up and down the idea behind the stellarator is that the magnetic field is twisted by the external magnetic field coils which means the plasma can be held in a steady state ‘What we are aiming for is to maintain the plasma for 30 minutes you can create the plasma and basically it stands there without interruption for hours What has held stellarators back until recently is getting the plasma right waves in the plasma create a constant mixture of uneven forces reacting to magnetic fields but also generating its own ‘We call that the “fluid picture” of a plasma,’ Prof We scientists only make a picture of reality and that is a useful picture how to describe what is happening.’  trying to expand and escape from its container And turbulence has caused a number of headaches fusion devices would be much smaller than what we have now because in order to counteract the heat loss Klinger explained.“‘What we are aiming for is to maintain the plasma for 30 minutes.’ That bigger amount offsets energy that escapes confinement through the surface ‘If you can find ways to reduce the turbulence … you make the heat insulation properties of the plasma better and you can basically build smaller machines,’ Prof While large 1 gigawatt fusion plants could be the backbone of an electrical network smaller machines could make easier-to-build power stations for industrial plants situated right inside cities That’s because unlike nuclear fission plants there is no chain reaction that needs to be carefully controlled if somebody pushes the wrong button or an aeroplane flies into the power station at a power station we are talking a maximum of 1 gram of plasma Compare that to the 30 000 ton weight of the machine Wendelstein 7-X International Thermonuclear Experimental Reactor Contact Horizon Experimental operation of the fusion reactor type stellarator kicks off with festive ceremony Federal Chancellor Angela Merkel actually pushed some buttons herself: on February 3 during a visit to the Wendelstein X-7 experimental fusion reactor at the Max Planck Institute of Plasma Physics (IPP) in Greifswald personally flipped the switch to generate the machine’s first hydrogen plasma "This marks the beginning of an experiment unique in the world which can bring us one step closer to the energy source of the future," the Chancellor said fired up in early December 2015 using helium; now it has started its experimental scientific operation the world’s largest and most advanced fusion device of the stellarator type researchers want to investigate this configuration’s suitability for use in a power plant the operational start of Wendelstein-7X is a milestone in its own history" Stratamnn went on to thank the Institute’s researchers: "You have achieved a true milestone in plasma physics and technical engineering on the road towards a sustainable energy supply in the 21st century." 2: The first hydrogen plasma in the Wendelstein 7-X was generated on 3 February 2016 It did not take the Chancellor long to find the button she was expected to press in order to switch on the first hydrogen plasma in Wendelstein 7-X  Staff members at the Max Planck Institute had placed it on a glass cube adorned with a laser-cut silhouette of the fusion plant and prominently positioned it on a steel column at the edge of the control room When Angela Merkel energetically pressed the glass cube a bright glow flickered on a monitor and provided a glimpse into the heart of the plasma vessel With the governmental switch of the button which marked the start of the device’s scientific experimental operation "Every step we are taking on the long road towards a fusion power plant is a success," Angela Merkel said one the world's most pressing questions is how we can address the increasing energy needs of a growing world population without missing our climate goals "The benefits of fusion energy are obvious: hydrogen as a fuel is available to an almost unlimited degree It is a clean energy source without climate-damaging CO2 emissions and long-lived radioactive waste In front of numerous guests from the realms of science and politics Federal Chancellor Angela Merkel triggered a 2-megawatt pulse of microwave heating which transformed a tiny quantity of hydrogen gas into an extremely hot low-density hydrogen plasma “With a temperature of 80 million degrees and a lifetime of a quarter of a second the device’s first hydrogen plasma has completely lived up to our expectations” whose division is responsible for operation of Wendelstein 7-X part of Werner Heisenberg’s vision has come true I am sure it would fill him with joy and pride to see us here today Such fusion plants stood at the beginning of a long development which might culminate in completely new possibilities of energy production "It is up to us to lay the scientific foundations for this showcasing options which can be used by society and politics when the time has come,” said the Max Planck President Observing the results of firing up the first hydrogen-plasma (from left to right): the two directors of the Max Planck Institute for Plasma Physics the President of the Helmholtz Association The booting up of first hydrogen plasma in the W7-X is to be followed by many other plasma experiments with the goal of clarifying fundamental questions of plasma research Chancellor Merkel also held a committed plea for basic research: "The example of nuclear fusion has clearly demonstrated what a drawn-out and costly process basic research can be Besides knowledge and a large portion of perseverance it also requires creativity as well as audacity." Those who dared to venture into unexplored territory often did not know where their chosen path would lead them Sometimes such paths would end in dead ends and sometimes they would lead to completely unexpected additional insights But without fundamental research certain findings could not be achieved Erwin Sellering also praised the research at the Max Planck Institute for Plasma Research as a long-term investment aimed at meeting rising energy demand in the future The Minister-President of Mecklenburg-Vorpommern congratulated the staff of the Institute on their contribution: "You carry out excellent work on the highest level." As Minister-President of Mecklenburg-Vorpommern he was proud that the scientists of the region positioned themselves so prominently in the global scientific landscape Before the Federal Chancellor fired the first hydrogen plasma in Wendelstein 7-X the researchers in Greifswald had started the fusion device on 10 December 2015 with an initial helium plasma Wendelstein 7-X has produced more than 300 discharges with the rare gas plasma heating and data recording were tested and the first measuring facilities for investigating the plasma were put into operation complex instrumentation such as X-ray spectrometers “This makes everything ready for the next step” “We are changing from helium to hydrogen plasmas The present initial experimentation phase will last until mid-March discharges lasting 30 minutes can be produced and it can be checked at the full heating power of 20 megawatts whether Wendelstein 7-X will achieve its optimisation targets Essential digital access to quality FT journalism on any device Complete digital access to quality FT journalism with expert analysis from industry leaders Complete digital access to quality analysis and expert insights complemented with our award-winning Weekend Print edition Terms & Conditions apply Discover all the plans currently available in your country Digital access for organisations. 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HomeDestinationsInterestsTop Places to Travel by MonthSearchMenuBest time to visit Bavaria Enjoy a spectacular alpine view and explore numerous highlights on Wendelstein mountain having been operating for more than a hundred years will take you up to the top of Wendelstein It's a 6,030-foot-high (1,838-m) mountain and the main attraction in the Upper Bavarian Limestone Alps The whole 30-minute ride is done at a speed of 12,5 miles (20 km) per hour ensuring you have some time to enjoy the scenic route The ride is 4,7 miles (7,6 km) long and takes you through seven tunnels The final station is located at an altitude of 5,653 feet (1,723 m) above sea level The railway operates every day from 9 am to 3 pm Another option is to explore an impressive cave or just enjoy the alpine view on 200 mountain peaks The best view can be found at Gacher Blick—a spectacular platform with an unforgettable panorama Special events are held during this period as well if you want to explore every part of this majestic mountain top the most suitable period is from May until November The new machine is designed to release energy in the same manner as the atoms in the sun This article appears in the 28 Oct 2015 issue of the New Statesman, Israel: the Third Intifada? preparations are underway to put the world’s largest stellarator into operation manufacturing components and assembling modules the fusion device is due to enter a new phase in May bringing scientists another step closer to generating electricity using the same principle as the sun In November 2011 it was still possible to look inside the Wendelstein 7-X: A worker is standing inside the bright yellow plasma vessel around which the solenoids are coiled The photograph also shows the supporting structure and the outer vessel that encases the numerous cooling pipes and power supply lines It all began in April 2005: slowly but surely the special gripper slides and rotates a magnetic coil weighing six tonnes onto an unconventionally shaped steel vessel The only sound to be heard in the assembly hall apart from the steering commands is the whirring of the crane Under the watchful eyes of their colleagues the assembly team threads the large coil onto the vessel with merely a finger’s breadth of space between the two elements After three hours the assembly test is complete: “The technology and the tools work and the personnel is well-trained,” concludes Lutz Wegener The solenoid and the vessel were the first components of the Wendelstein 7-X fusion device to come to Greifswald from the different manufacturing plants across Europe is home to a sub-institute established by the MPI for Plasma Physics (IPP Bavaria) in 1994 in the course of Forschungsaufbau Ost a federal programme designed to foster scientific research in eastern Germany both facilities have been conducting complementary research and working towards the same goal: to emulate the sun’s method of producing energy here on earth The aim is to generate electricity by fusing together atomic nuclei in a fusion power plant Due to the fact that the fusion fire does not ignite until it reaches a temperature of over 100 million degrees the fuel – a low-density hydrogen plasma – must not come into contact with material walls Magnetic fields therefore keep the fuel suspended inside a vacuum chamber to prevent contact This magnetic cage can take one of two forms: while the Tokamak ASDEX Upgrade in Garching is in operation the Wendelstein 7-X stellarator is being constructed near the coast of the Baltic Sea in Greifswald View into the experimentation hall: The main installation of Wendelstein 7-X is completed tokamaks are still the leading technology in this field due to their simpler construction design Only one tokamak – such as the ITER international test reactor – is currently thought to be capable of producing energy-supplying plasma “However,” says project head Thomas Klinger “we have reason to believe that the stellarator principle will prevail where its competitor shows weakness.” This is because stellarators are suitable for continuous operation – thanks to the specially constructed magnetic system surrounding them Its structure is the result of sophisticated calculations and optimisation efforts by the “Stellarator Theory” Group which spent ten years searching for a particularly stable and heat-insulating magnetic cage “The aim of the Wendelstein 7-X is to put the quality of the plasma balance and confinement on par with that of a tokamak for the first time The experiment is designed to show that stellarators are suitable for use in power plants the stellarator is due to demonstrate its main asset: continuous operation The device consists of five virtually identical modules that were pre-assembled in an experiment hall and combined to form a large ring: 70 superconducting coils the solenoids are later cooled down to a superconducting temperature close to absolute zero using liquid helium so that they use up hardly any energy anymore the assembly team also installed miles of cooling pipes conductors and measuring cables as well as numerous observation ports and sensors while constantly reviewing the measurements of the many thousands of weld seams and checking for any leaks “In the case of a device as complex as this one the industrial production and assembly are an experiment in their own right,” explains Lutz Wegener “We had initially underestimated the enormity of the task,” admits Klinger: “The superconducting technology together with the demanding geometry of the components meant we were faced with extreme requirements.” Constructing and manufacturing measuring and calculating – the complex shapes called for methods that the Institute and the industry could only develop once the project was already underway The project master plan was revised in 2007 Wendelstein 7-X is right on target in terms of both time and costs,” says Klinger To celebrate the fact that the researchers are preparing to put the device into operation an official ceremony will be held in Greifswald on 20 May In addition to fusion researchers from all across Europe the event will also be attended by Max Planck President Peter Gruss as well as by dignitaries from the field of politics including Germany’s Federal Minister of Education and Research all of the technical systems will be tested one by one: the vacuum inside the vessels we can begin generating plasma in about a year from now,” says Klinger Nuclear fusion is, after all, what powers the Sun and other stars so it’s an energy source with a pretty nifty pedigree they injected a minute quantity of hydrogen into an elaborate machine that resembles something out of a Star Wars movie and mimicked the conditions within the Sun by heating that hydrogen gas until it became a plasma In the press release they note that this is just the latest step in the project "Since the start of operation on 10 December 2015 Wendelstein 7-X has produced more than 300 discharges with the rare gas finally attaining six million degrees....'This makes everything ready for the next step,' states Project Head Professor Dr 'We are changing from helium to hydrogen plasmas our proper subject of investigation.'" The device is located at the Max Planck Institute in Greifswald, Germany, and is known as the Wendelstein 7-X Stellarator (W7-X for short) which certainly sounds like something a Bond villain might use to take over the world But the uses to which this incredible instrument will be put are far more benign A “stellarator” is a conceptual fusion reactor design conceived in 1950 by the American physicist Lyman Spitzer; it is similar to the better-known “tokamak” fusion reactor design which is essentially a doughnut-shaped machine that uses powerful electric currents to bottle the plasma needed to trigger a fusion reaction it utilizes a complex array of magnetic coils to contain the plasma but easier to operate,” said Thomas Klinger project leader for the Greifswald experiment At 400 million euros ($435 million) it certainly wasn’t cheap to build, either.  But the world is eagerly investing in such experimental technology, hoping to reap enormous dividends if successful ignition is achieved.  France, for example, has begun construction on ITER (International Thermonuclear Experimental Reactor) a more conventional tokamak design; and there are several projects underway in the United States The infinite promise of fusion power has touched off a worldwide scramble to achieve the first sustained controlled fusion reaction; the W7-X’s designers hope their machine will be an important step on this road "It’s a very clean source of power, the cleanest you could possibly wish for.  We’re not doing this for us, but for our children and grandchildren," explains John Jelonnek, a member of the W7-X team. "With a temperature of 80 million degrees and a lifetime of a quarter of a second, the device’s first hydrogen plasma has completely lived up to our expectations," adds Dr. Hans-Stephan Bosch, whose division is responsible for operation of Wendelstein 7-X. The purpose of the Greifswald stellarator is not to actually produce any energy itself.  It’s an experimental device, designed to test the conditions expected to obtain within a functioning fusion reactor, and shake out any unexpected problems that might crop up. The experiment that began this week is only the first of many that will, hopefully, lead to an operational reactor in the coming decades.  The frenetic research being conducted throughout the world should only help to shorten the period of our anticipation and our reliance on dirty and harmful sources of power. So stay tuned.  The search for clean fusion energy continues. 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Members of MIT’s Plasma Science and Fusion Center (PSFC) community are cheering the start of a long-anticipated physics experiment at the Max Planck Institute for Plasma Physics in Greifswald Two teams of PSFC researchers are collaborating on the Wendelstein 7-X device the world’s largest fusion experiment designed in the stellarator line of magnetic confinement fusion devices The PSFC has significant experience with a different configuration of magnetic confinement having spent decades designing and running the Alcator series of high-magnetic-field tokamak experiments; the Alcator C-Mod device There are many similarities between the two designs Both the tokamak and the stellarator seek to harness the energy released from the fusion of hydrogen isotopes to provide clean and safe electrical power Both use helical (spiraling) magnetic fields to contain the hot plasma fuel in a donut-shaped chamber this field is generated both by external electromagnets and a large electrical current that is driven in the plasma itself Driving and sustaining this plasma current and its impact on stability and transport of energy and particles The stellarator concept takes a different approach First invented by the noted astrophysicist and fusion pioneer Lyman Spitzer of Princeton University in 1950 the stellarator provides the entire helical field through external electromagnets formed in highly complex and twisted shapes Although the assembly of a modern stellarator like W7-X presents many engineering challenges this approach has significant operational advantages Because there is no need to drive a current in the plasma the configuration is more readily extrapolated to steady-state a necessity for economic operation of a fusion power plant The magnetic field geometry of Wendelstein 7-X has been optimized using super-computer simulations of particle orbits W7-X has super-conducting coils and is designed to create and sustain hot plasma for up to 30 minutes The immediate goal of these experiments is to demonstrate that the loss of particles can be kept small so that high temperatures can be achieved In early phases of the experiment up to 10 megawatts of microwave power will be used to heat the plasma as much as 8 megawatts of neutral-beam power will be added after water-cooled armor is installed to handle the exhaust heat W7-X expects to produce plasmas with fusion-grade densities and temperatures 60-130 million kelvins Future experiments at W7-X will address the role that plasma turbulence plays in limiting overall performance and PSFC researchers are working with the W7-X group to investigate this One PSFC team — comprised of principal research scientist Jim Terry and postdoc Seung-Gyou Baek — will develop a fast camera system for viewing light emitted from the plasma and will make important measurements of turbulence near the edge of the plasma The other team — professor of physics Miklos Porkolab and staff scientist Eric Edlund — will develop a specialized interferometer for imaging density fluctuations deep in the hot plasma core The issues surrounding turbulence are important in stellarators since turbulence moves heat and particles across the confining magnetic field faster than would otherwise occur Both teams expect to have first measurements during the 2017 experimental campaign Department of Energy Office of Fusion Energy Sciences and the Max Planck Institute for Plasma Physics This website is managed by the MIT News Office, part of the Institute Office of Communications Massachusetts Institute of Technology77 Massachusetts Avenue The plasma researchers’ efforts and patience have paid off a good ten years after the assembly of the Wendelstein 7-X fusion device began at the Max Planck Institute for Plasma Physics (IPP) in Greifswald physicists produced the first helium plasma After over a year of technical preparation and tests the world’s largest stellarator-type fusion device the researchers would like to prove that this type of device is suitable for use as a power station The first plasma in the Wendelstein 7-X fusion device in Greifswald presents itself with a bright glow It consisted of helium and reached a temperature of about one million degrees Celsius After a construction period of nine years and over one million assembly hours the main construction work on the Wendelstein 7-X came to an end in April 2014 Preparation for the operation of the fusion device has been under way ever since Scientists and technicians tested all of its components in turn; the vacuum in the vessels the superconducting coils and the magnetic field they produce and the heating devices and measuring instruments The time had finally come on December 10th: the operating team in the control room started up the magnetic field in which the plasma is confined so that it does not come into contact with the wall of the plasma chamber and cools down The experiment’s computer-operated control system was then activated It fed around one milligram of helium gas into the plasma vessel from which the air had already been evacuated The team then switched on the microwave heating for a short 1.8-kilowatt pulse – and the first plasma could be observed by the installed cameras and measuring devices “We’re starting with a plasma produced from the noble gas helium We will not change over to the actual test object until next year,” explains project leader Thomas Klinger Director at Max Planck Institute for Plasma Physics (IPP) and head of the Wendelstein 7-X project “This is because it’s easier to achieve the plasma state with helium we can clean the surface of the plasma vessel with helium plasmas,” he adds The first plasma in the machine lasted one tenth of a second and reached a temperature of around one million degrees  “We’re very satisfied,” says Hans-Stephan Bosch whose division is responsible for the operation of the Wendelstein 7-X “Everything went according to plan.”   the researchers want to extend the duration of the plasma discharges and to investigate the best method for producing and heating helium plasmas using microwaves confinement studies will resume in January when the scientist will test how well the helium plasma is confined in the magnetic field the scientists will prepare the way for the first experiments with hydrogen plasma which is ultimately intended to be fused into helium in the fusion experiments The objective of fusion research is to develop a climate- and environmentally-friendly power plant harvests energy from the fusion of atomic nuclei As the fusion fire only ignites at temperatures in excess of 100 million degrees the fuel – a thin hydrogen plasma – must not come into contact with cold vessel walls it floats almost entirely contact-free in the interior of a vacuum chamber Two different designs for the magnetic cage have become established – the tokamak and the stellarator Both types of system are being tested at the IPP The Tokamak ASDEX Upgrade is in operation in Garching and the Wendelstein 7-X stellarator is operational in Greifswald A loop for diagnostics: a technician inserts a diamagnetic coil into the plasma vessel of the Wendelstein 7-X This instrument will measure the change in the magnetic flow an important parameter of the magnetic field for the plasma confinement Many scientists currently believe that a tokamak – the international test reactor ITER which is currently being constructed in Cadarache as part of a worldwide collaborative project – is the only system capable of producing an energy-supplying plasma the world's largest stellarator-type fusion device it should demonstrate that stellarators are also suitable for use as power plants Using the Wendelstein 7-X it is intended to demonstrate for the first time that a stellarator can confine a plasma as well as a tokamak the stellarator should also demonstrate its crucial advantage – the ability to operate continuously without the help of complicated supplementary measures The assembly of Wendelstein 7-X began in April 2005: a ring of 50 superconducting coils The special shapes of the coils are the result of refined optimization calculations carried out by the IPP’s “Stellarator Theory” division which spent over ten years searching for a magnetic cage that is particularly heat insulating The coils are threaded onto a ring-shaped steel plasma vessel and encased by a steel shell the coils are cooled down to superconduction temperature close to absolute zero using liquid helium The magnetic cage they create keeps the 30 cubic metres of ultra-thin plasma – the test object – suspended inside the plasma vessel The investment costs of the Wendelstein 7-X total EUR 370 million and were provided by the German federal and federal state governments and the EU The components were manufactured by companies throughout Europe Orders in excess of EUR 70 million were placed with companies in the region Numerous research facilities at home and abroad were involved in the construction of the device As part of the Helmholtz Association of German Research Centres the Karlsruhe Institute of Technology was responsible for the microwave plasma heating; the Forschungszentrum Jülich built measuring instruments and produced the complex connections for the superconducting magnetic coils The installation was carried out by experts from the Polish Academy of Sciences in Krakow The American fusion research institutes at Princeton Oak Ridge and Los Alamos contributed equipment for the Wendelstein 7-X which included auxiliary coils and measuring instruments Invests millions to launch a US research programme on German device The USA is investing 7.5 million dollars for the construction of the fusion device Wendelstein 7-X at the Max Planck Institute for Plasma Physics (IPP) in Greifswald said he was delighted about the US involvement: "This contribution is testimony to the outstanding scientific performance of the Max Planck Institute for Plasma Physics as well as to the importance of the experimental approach in Greifswald But it also reflects the great interest of the United States in fusion research the funds that are being invested all come from the "Innovative Approaches to Fusion" programme of the US Department of Energy." The outer vessel of Wendelstein 7-X is equipped with a variety of ports which are provided by Princeton Plasma Physics Laboratory They are to help precise setting of the magnetic fields at the plasma edge scientists from the fusion institutes at Princeton Oak Ridge and Los Alamos are contributing auxiliary magnetic coils measuring instruments and planning of special sections of the wall cladding for equipping the German fusion device the USA will accordingly become a partner in the Wendelstein 7-X research programme.The objective of fusion research is to develop a power plant that derives energy from fusion of atomic nuclei This requires that the fuel – an ionised low-density gas a plasma – be confined in a magnetic field cage having virtually no contract with the vessel wall and then be heated to an ignition temperature of over 100 million degrees now being built at Max Planck Institute of Plasma Physics in Greifswald be the world’s largest and most modern device of the stellarator type Its magnetic field makes continuous operation possible by simple means In the German-American cooperation programme Princeton Plasma Physics Laboratory is making five auxiliary coils for Wendelstein 7-X to be installed on the outer casing of the device are to help precise setting of the magnetic fields at the plasma edge They ensure that the outer contour of the plasma exactly conforms to the required shape The basic data for the components are provided by IPP engineers and scientists from Princeton are in charge of design – which has just undergone the final check – and manufacture of the coils They are to be delivered at the end of 2012 The 4.3 million-dollar investment for this constitutes the major contribution to the scientific cooperation on Wendelstein 7-X Oak Ridge National Laboratory is taking on design of the scraper elements for the plasma edge of Wendelstein 7-X The new components being introduced into planning are to enhance the device’s performance in continuous operation and ensure greater experimental flexibility The water-cooled plates have to withstand heavy heat loads of up to 20 megawatts per square metre This will make it possible to protect wall sections across which the hot plasma will move to its final position in the first 30 seconds of the 30-minute plasma discharges The sophisticated technology study is to be ready by the end of the year Los Alamos National Laboratory will provide the Wendelstein programme with measuring instruments for observing the plasma including refined infrared diagnostics: “We envision this three-year period” “as a step toward a robust partnership in the Wendelstein 7-X research program that will involve physicists and engineers from many U.S institutions in research that will make a significant impact on the world fusion program.” the nuclear fusion device is the largest stellarator ever constructed using 50 computer-designed electromagnets to guide superheated plasma around its 16m-long toroidal chamber The project has taken two decades to reach this point and is potentially a key step towards nuclear fusion power plants that will provide clean and virtually limitless energy approximately 2,200 plasma pulses have been fired since operations began building from initial lengths of half a second up to six seconds At mean plasma densities the physicists were able to generate temperatures of 100 million degrees Celsius for the plasma electrons These temperatures were recorded using 4 megawatt microwave pulses lasting one second You’ve now reached your monthly limit of news stories Register for free to unlock unlimited access to all of our news coverage as well as premium content including opinion The largest and most advanced fusion experiment of its kind in the world launched this week Princeton Plasma Physics Laboratory (PPPL) physicists collaborating on the Wendelstein 7-X (W7-X) stellarator fusion energy device in Greifswald 3 when German Chancellor Angela Merkel pushed a button to produce the reactor's first plasma of hydrogen-fueled superhot gas.  a device that uses twisted magnetic coils to confine the plasma that fuels fusion reactions in a three-dimensional and steady-state magnetic field It is a departure from the more common fusion device used in fusion experiments a donut-shaped device called a "tokamak" such as that used at PPPL.  The German reactor is the result of an international collaboration and PPPL's Hutch Neilson was the coordinator of the U.S "It was a day of building excitement and it was a very happy mood because everything is working really well on the experiment," said Neilson "It was kind of amazing when the chancellor walked into the control room Princeton University vice president for the Princeton Plasma Physics Laboratory and German Chancellor Angela Merkel shake hands in the Wendelstein 7-X control room at the celebration of the first hydrogen plasma (Photo courtesy of the Max Planck Institute for Plasma Physics) Scientists and dignitaries from around the world watched as Merkel pushed the button to create a hydrogen plasma that lasted a quarter of a second But that was long enough to begin heating the plasma to 80 million degrees Celsius the W7-X is designed to produce a plasma that lasts up to 30 minutes and would demonstrate that stellarators could be a model for the fusion power plants of the future.  Merkel acknowledged that there are "huge scientific challenges" and costs associated with developing fusion energy but she said the possibility of developing fusion energy as a source of generating electric energy is worth the investment.  "Rising energy demands and the vision of an almost inexhaustible energy source are convincing arguments for investing in fusion," Merkel said.  Neilson and Princeton University Vice President for PPPL A.J Stewart Smith were among the select group of scientists in the W7-X control room Department of Energy Associate Director of Science for Fusion Energy Sciences PPPL physicists Samuel Lazerson and Novimir Pablant also attended the event along with other U.S Smith said the W7-X is a significant achievement that will lead to "major progress for the understanding of plasma."  "The W7-X is a major step for fusion research team are absolutely thrilled," Smith said to Merkel in German "We are so pleased to be involved in this exceptional event.  "I am very impressed by the professional way the IPP team was able to successfully build such a complex daunting machine," Smith said "The success of W7-X shows that the daunting challenges facing stellarators have been solved."  The hydrogen plasma is "a step on the path to making the device perform as planned," said David Gates a PPPL physicist and stellarator physics lead who was on hand at W7-X for the first test plasma and watched a live stream of the first hydrogen plasma in the PPPL auditorium this next phase of research is an important milestone."  which is funded by $4 million annually from the Department of Energy's Office of Science PPPL scientists and technicians built some key components of the machine which took some 20 years and 1 billion euro to build.  PPPL physicist Novimir Pablant and Andreas Langenberg work in front of the housing for components of the X-Ray crystal spectrometer built by Pablant and PPPL engineer Michael Mardenfeld PPPL researchers designed and delivered the five massive 2,400-pound trim coils that fine-tune the shape of plasma in fusion experiments Physicists also designed and built an X-ray spectrometer for measuring the plasma temperature A current project is the design and construction of divertor scraper units that intercept heat from the plasma to protect divertor targets from damage.  Collaborators include researchers from Los Alamos and Oak Ridge National Laboratories as well as researchers and students from the Massachusetts Institute of Technology Neilson said the experiment is already getting good results. "We're getting data and physics results from it exceeding expectations for what everybody thought would be accomplished during this startup period," he said.  PPPL researchers have already collaborated on research at the W7-X Lazerson has been at the W7-X since March 2015 and performed one of the first experiments on the machine when he mapped the structure of the magnetic field and proved that the main magnet system and the trim coils that PPPL designed and had built in the U.S He presented his research at the APS Division of Plasma Physics Conference in November. Pablant used the X-ray spectrometer to make the first plasma temperature measurements on W7-X "I was really proud of the American contingent for the work they've done," Neilson said the evening of the event "We've made ourselves as indispensable as it's possible to be Stellarators and tokamaks are two different approaches to the same difficult challenge of developing fusion as an energy source and the W7-X is putting more attention on the potential of stellarators "The arrival of W7-X on the scene creates sort of a buzz about stellarators," Neilson said which is competitive with anything that's out there in terms of capabilities is just bound to shift the conversation about stellarators."  PPPL has taken a different approach to stellarators with its quasi-axisymmetric stellarator or QUASAR the focus is going to be on W7-X itself," he said "but it does create an atmosphere in which it's reasonable to ask which is the largest single supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time.  One of the world's leading plasma research facilities just broke a new record, showing we really are getting closer to the wonderful goal of fusion power - a virtually limitless supply of clean energy Experiments on the Wendelstein 7-X stellarator – a device that uses magnets to confine clouds of plasma (hot charged gas) – suggest its specific design could be the way to go generating more power than any other machine of its kind Wendelstein 7-X first fired up at the Max Planck Institute for Plasma Physics in late 2015 it could hold in place a loop of helium ions heated to a million degrees That may not sound like much if we're going to use this tech to produce energy, but bear with us. The machine was never intended to operate as a power station – it's a test-bed for finding ways to squeeze as much as we can from nuclear fusion technology And it's doing a surprisingly fine job of it In the latest tests, with 18 times more energy fed into the W 7-X than in previous tests, the ions of helium zipping through the plasma reached a sizzling 40 million degrees Kelvin – four times hotter than before While most of us are familiar with typical nuclear energy - the decay of big atoms being used to generate electricity - fusion energy is released when atoms are instead welded together Since it doesn't produce the same kind of radiation woes that atom-splitting power creates it's the most promising energy source of the future apart from the irradiated panels lining the inside of the reactor fusion is as clean as power production gets Fusion fuel is also in such vast supply that we might as well think of it as an unlimited power source we're talking in the vicinity of 100 million degrees of kicking and this requires a specific type of machine Machines like MIT's Alcator C-Mod tokamak use the electromagnetic fields generated by the resulting plasma to help keep the writhing jelly doughnut of charged particles in line This keeps the hot cloud of slam-dancing particles nice and tight generating impressive amounts of energy when fuel is injected But it suffers from instabilities that make power production an all-too-brief affair Meanwhile, stellarators like the W 7-X rely on banks of magnetic coils to contain the plasma offering greater control that means that hot ring of helium jelly can keep swirling for longer periods They don't quite match the tokamak in terms of output but the latest record-breaking feat looks like W 7-X's 15 metre wide machine is showing us a way to bridge that gap Recent rounds of experiments have also resulted in a leap in containment time from a maximum of 6 seconds of comparable plasma generation to around 25 seconds but it's again a leap in the right direction "This is an excellent value for a device of this size, achieved, moreover, under realistic conditions," says physicist Thomas Sunn Pedersen from the Max Planck Institute The improvements were in part due to the addition of a new type of interior cladding which helps manage the flow of the plasma by diverting stray particles that affect the plasma flow The next round of operations will focus on changes to this cladding pushing the plasma to even higher densities and temperatures Analysis on the first round of experimentation in 2016 has also revealed the methods they've used to optimise the entire process have given the right results "More exact and systematic evaluation will ensue in further experiments at much higher heating power and higher plasma pressure," says the study's first author Andreas Dinklage This still doesn't mean we can nail down a date for fusion There are still plenty of wrinkles to iron out and for all of their promise stellarators still have a way to go before they can break even and generate more than they produce Then there is the question of fuel. The helium in the reactor is a product of hydrogen atoms fusing together. But it's not just any hydrogen – a favoured variety called tritium isn't found in significant reserves on Earth so needs to be produced in a reactor or harvested elsewhere Fusion remains just over the horizon for now But results of experiments like these show that we're heading towards that horizon at breakneck speed so we're right to feel cautiously optimistic here This research was published in Nature A nice-looking heritage-style boot that is very comfortable the Lowa Wendelstein II W performs well on easy to moderate trails Sole isn’t as aggressive as some other boots Its maker recommends the Lowa Wendelstein II W for walking and casual use Translation: they’re suited to striding up any mountain meadow to an alpine hut as well as more casual outings on recreational paths Crafted with rugged full-grain leather on the outside and a buttery glove leather lining this heritage hiking and walking boot is beautiful enough to wear around town and technical enough for low alpine mountain wanders in decent conditions It’s also surprisingly light for a full leather boot The Lowa Wendelstein II W grew more comfortable and better looking the more I wore it the glove leather inside formed to my foot and felt almost customized to my feet with time Metal D-ring lace loops made it easy to pull the Wendelstein’s laces and snug it to my foot The boots comes with an extra set so I could add a dash of color to these classic and neutral kicks when I was in the mood However, the Wendelstein doesn’t have the squishy midsole characteristic of many modern hiking boots The midsole is a medium-thin layer of EVA for shock absorption – the same stuff used to give sneakers their springy feel – but the Wendelstein uses a thin layer not the thick pad found in most running shoes a hike to a viewpoint and countryside rambles but on long treks I lost the spring in my step sooner than in boots with more midsole Vibram’s Marmolada sole had good grip in easy to moderate terrain and in this stitched boot the sole is replaceable when it wears out Not only does that lower the environmental impact of these boots – because they won’t be landfill-bound once the sole wears out – it also means I get to keep them for longer Berne BroudyVermont-based writer climbing and kayaking for category-leading publications in the U.S. she’s been asked to deliver a herd of llamas to a Bolivian mountaintop corral helped establish East Greenland’s first sport climbing and biked the length of Jordan She’s worked to help brands clean up their materials and manufacturing and has had guns pulled on her in at least three continents.