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99 results on '"Oosterbeek, J. W."'

1. Development of the 174 GHz collective Thomson scattering diagnostics at Wendelstein 7-X

Author

Ponomarenko, S., Moseev, D., Stange, T., Krier, L., Stordiau, P., Braune, H., Gantenbein, G, Jelonnek, J., Kuleshov, A., Laqua, H. P., Lechte, C., Marsen, S., Nielsen, S. K., Oosterbeek, J. W., Plaum, B., Ragona, R., Rasmussen, J., Ruess, T., Salewski, M, Thumm, M., Zimmermann, J., Ponomarenko, S., Moseev, D., Stange, T., Krier, L., Stordiau, P., Braune, H., Gantenbein, G, Jelonnek, J., Kuleshov, A., Laqua, H. P., Lechte, C., Marsen, S., Nielsen, S. K., Oosterbeek, J. W., Plaum, B., Ragona, R., Rasmussen, J., Ruess, T., Salewski, M, Thumm, M., and Zimmermann, J.

Abstract

In this paper, we present the design and commissioning results of the upgraded collective Thomson scattering diagnostic at the Wendelstein 7-X stellarator. The diagnostic has a new radiometer designed to operate between the second and third harmonics of the electron cyclotron emission from the plasma at 171-177 GHz, where the emission background has a minimum and is of order 10-100 eV. It allows us to receive the scattered electromagnetic field with a significantly improved signal-to-noise ratio and extends the set of possible scattering geometries compared to the case of the original instrument operated at 140 GHz. The elements of the diagnostic are a narrowband notch filter and a frequency stabilized probing gyrotron that will allow measuring scattered radiation spectra very close to the probing frequency. Here, we characterize the microwave components applied to the radiometer and demonstrate the performance of the complete system that was achieved during the latest experimental campaign, OP2.1.

Published
2024

2. Microwave stray radiation losses in vacuum windows

Author

Oosterbeek, J. W., Stern, M., Braune, H., Ewert, K., Hirsch, M., Hollmann, F., Laqua, H. P., Marsen, S., Meier, A., Moseev, D., Noke, F., Reintrog, A., Stange, T., Wolf, R. C., and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Loss tangent, Nuclear Energy and Engineering, Vacuum window losses, Mechanical Engineering, Microwave stray radiation, General Materials Science, ddc:620, Engineering & allied operations, W7-X, Civil and Structural Engineering, ECRH, Dielectric losses
Abstract

Vacuum windows are required in magnetically confined fusion experiments to provide possibilities to observe the plasma in a wide range of electromagnetic wavelengths. The window disk consists of a dielectric, e.g. Fused Silica (SiO$_2$), Sapphire or Chemically Vapourised Diamond (CVD). As electromagnetic waves pass through the disk, a fraction of the beam power is dissipated resulting in a temperature increase of the disk. In Electron Cyclotron Waves (ECW) heated plasmas the dissipation in the window disk can be very high. The computation of dielectric losses for a collimated beam with known incidence angle, polarisation and loss tangent (measure for the intrinsic dielectric loss) is well established. However, the dielectric losses in diagnostic windows mostly result from microwave stray radiation, which results from a modest, but inevitable, fraction of non-absorbed ECW. This fraction diffuses in the vessel by many reflections into rays with random k-vector and with random polarisation. In this work the thermal load on the window disk by microwave stray radiation is assessed. The load by a collimated beam is studied as a function of incidence angle and polarisation allowing to average over a distribution of incident rays. An experiment was commissioned measuring the loss tangent of a number of commercially available SiO$_2$ disks at low power in an open resonator, and subsequently measuring the dielectric heating of these disks at high power stray radiation using the facility ’MISTRAL’ at Wendelstein-7X. The experimental results are compared to modelling and it is demonstrated that, in the parameter range considered, single-pass fractional absorption may be applied while taking a safety margin that arises from the minima and maxima due to multiple reflections.

Published
2022
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3. Demonstration of reduced neoclassical energy transport in Wendelstein 7-X

Author

W7-X Team, Beidler, C. D., Smith, H. M., Alonso, A., Andreeva, T., Baldzuhn, J., Beurskens, M. N. A., Borchardt, M., Bozhenkov, S. A., Brunner, K. J., Damm, H., Drevlak, M., Ford, O. P., Fuchert, G., Geiger, J., Helander, P., Hergenhahn, U., Hirsch, M., Höfel, U., Kazakov, Ye. O., Kleiber, R., Krychowiak, M., Kwak, S., Langenberg, A., Laqua, H. P., Neuner, U., Pablant, N. A., Pasch, E., Pavone, A., Pedersen, T. S., Rahbarnia, K., Schilling, J., Scott, E. R., Stange, T., Svensson, J., Thomsen, H., Turkin, Y., Warmer, F., Wolf, R. C., Zhang, D., Abramovic, I., Äkäslompolo, S., Alcusón, J., Aleynikov, P., Aleynikova, K., Ali, A., Anda, G., Ascasibar, E., Bähner, J. P., Baek, S. G., Balden, M., Banduch, M., Barbui, T., Behr, W., Benndorf, A., Biedermann, C., Biel, W., Blackwell, B., Blanco, E., Blatzheim, M., Ballinger, S., Bluhm, T., Böckenhoff, D., Böswirth, B., Böttger, L.-G., Borsuk, V., Boscary, J., Bosch, H.-S., Brakel, R., Brand, H., Brandt, C., Bräuer, T., Braune, H., Brezinsek, S., Brunner, K.-J., Burhenn, R., Bussiahn, R., Buttenschön, B., Bykov, V., Cai, J., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chaudhary, N., Chauvin, D., Chernyshev, F., Cianciosa, M., Citarella, R., Claps, G., Coenen, J., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czerski, K., Czerwinski, M., Czymek, G., Molin, A. da, Silva, A. da, Pena, A. de la, Degenkolbe, S., Dhard, C. P., Dibon, M., Dinklage, A., Dittmar, T., Drewelow, P., Drews, P., Durodie, F., Edlund, E., Effenberg, F., Ehrke, G., Elgeti, S., Endler, M., Ennis, D., Esteban, H., Estrada, T., Fellinger, J., Feng, Y., Flom, E., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Fornal, T., Frerichs, H., Freund, A., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., García Regaña, J., Gates, D., Geiger, B., Giannella, V., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Greuner, H., Grosman, A., Grote, H., Gruca, M., Grulke, O., Guerard, C., Hacker, P., Han, X., Harris, J. H., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Henneberg, S., Henkel, M., Hernandez Sanchez, J., Hidalgo, C., Hollfeld, K. P., Hölting, A., Höschen, D., Houry, M., Howard, J., Huang, X., Huang, Z., Hubeny, M., Huber, M., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Jablonski, S., Jakubowski, M., Jelonnek, J., Jenzsch, H., Jesche, T., Jia, M., Junghanns, P., Kacmarczyk, J., Kallmeyer, J.-P., Kamionka, U., Kasahara, H., Kasparek, W., Kenmochi, N., Killer, C., Kirschner, A., Klinger, T., Knauer, J., Knaup, M., Knieps, A., Kobarg, T., Kocsis, G., Köchl, F., Kolesnichenko, Y., Könies, A., König, R., Kornejew, P., Koschinsky, J.-P., Köster, F., Krämer, M., Krampitz, R., Krämer-Flecken, A., Krawczyk, N., Kremeyer, T., Krom, J., Ksiazek, I., Kubkowska, M., Kühner, G., Kurki-Suonio, T., Kurz, P. A., Landreman, M., Lang, P., Lang, R., Langish, S., Laqua, H., Laube, R., Lazerson, S., Lechte, C., Lennartz, M., Leonhardt, W., Li, C., Li, Y., Liang, Y., Linsmeier, C., Liu, S., Lobsien, J.-F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., Lücke, A., Lumsdaine, A., Lutsenko, V., Maaßberg, H., Marchuk, O., Matthew, J. H., Marsen, S., Marushchenko, M., Masuzaki, S., Maurer, D., Mayer, M., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, P., Mikkelsen, D., Mishchenko, A., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., Mönnich, T., Morisaki, T., Moseev, D., Murakami, S., Náfrádi, G., Nagel, M., Naujoks, D., Neilson, H., Neu, R., Neubauer, O., Ngo, T., Nicolai, D., Nielsen, S. K., Niemann, H., Nishizawa, T., Nocentini, R., Nührenberg, C., Nührenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., Ölmanns, J., Ongena, J., Oosterbeek, J. W., Orozco, G., Otte, M., Pacios Rodriguez, L., Panadero, N., Panadero Alvarez, N., Papenfuß, D., Paqay, S., Pawelec, E., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., Pölöskei, P., Porkolab, M., Proll, J., Puiatti, M.-E., Puig Sitjes, A., Purps, F., Rack, M., Récsei, S., Reiman, A., Reimold, F., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Risse, K., Rohde, V., Röhlinger, H., Romé, M., Rondeshagen, D., Rong, P., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Salewski, M., Samartsev, A., Sanchez, M., Sano, F., Satake, S., Schacht, J., Satheeswaran, G., Schauer, F., Scherer, T., Schlaich, A., Schlisio, G., Schluck, F., Schlüter, K.-H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, P., Schrittwieser, R., Schröder, M., Schröder, T., Schroeder, R., Schumacher, H., Schweer, B., Sereda, S., Shanahan, B., Sibilia, M., Sinha, P., Sipliä, S., Slaby, C., Sleczka, M., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Stejner, M., Stephey, L., Stridde, U., Suzuki, C., Szabó, V., Szabolics, T., Szepesi, T., Szökefalvi-Nagy, Z., Tamura, N., Tancetti, A., Terry, J., Thomas, J., Thumm, M., Travere, J. M., Traverso, P., Tretter, J., Trimino Mora, H., Tsuchiya, H., Tsujimura, T., Tulipán, S., Unterberg, B., Vakulchyk, I., Valet, S., Vanó, L., Eeten, P. van, Milligen, B. van, Vuuren, A. J. van, Vela, L., Velasco, J.-L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Stechow, A. von, Vorköper, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Wang, Z., Wauters, T., Wegener, L., Weggen, J., Wegner, T., Wei, Y., Weir, G., Wendorf, J., Wenzel, U., Werner, A., White, A., Wiegel, B., Wilde, F., Windisch, T., Winkler, M., Winter, A., Winters, V., Wolf, S., Wright, A., Wurden, G., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zanini, M., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zocco, A., Zoletnik, S., Zuin, M., W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society, Applied Physics and Science Education, Science and Technology of Nuclear Fusion, Turbulence in Fusion Plasmas, and European Commission

Subjects
Magnetically Confined Plasmas, Tokamak, Design, Helias, Nuclear engineering, Magnetically confined plasmas, 01 natural sciences, 7. Clean energy, Article, Plasma physics, 010305 fluids & plasmas, law.invention, law, Physics::Plasma Physics, 0103 physical sciences, Nuclear fusion, 010306 general physics, Engineering & allied operations, Stellarator, Physics, Plasma fusion, Multidisciplinary, Toroid, biology, Plasma Physics, Física, Magnetic confinement fusion, Plasma, biology.organism_classification, Energía Nuclear, ddc:620, Wendelstein 7-X
Abstract

Research on magnetic confinement of high-temperature plasmas has the ultimate goal of harnessing nuclear fusion for the production of electricity. Although the tokamak1 is the leading toroidal magnetic-confinement concept, it is not without shortcomings and the fusion community has therefore also pursued alternative concepts such as the stellarator. Unlike axisymmetric tokamaks, stellarators possess a three-dimensional (3D) magnetic field geometry. The availability of this additional dimension opens up an extensive configuration space for computational optimization of both the field geometry itself and the current-carrying coils that produce it. Such an optimization was undertaken in designing Wendelstein 7-X (W7-X)2, a large helical-axis advanced stellarator (HELIAS), which began operation in 2015 at Greifswald, Germany. A major drawback of 3D magnetic field geometry, however, is that it introduces a strong temperature dependence into the stellarator’s non-turbulent ‘neoclassical’ energy transport. Indeed, such energy losses will become prohibitive in high-temperature reactor plasmas unless a strong reduction of the geometrical factor associated with this transport can be achieved; such a reduction was therefore a principal goal of the design of W7-X. In spite of the modest heating power currently available, W7-X has already been able to achieve high-temperature plasma conditions during its 2017 and 2018 experimental campaigns, producing record values of the fusion triple product for such stellarator plasmas3,4. The triple product of plasma density, ion temperature and energy confinement time is used in fusion research as a figure of merit, as it must attain a certain threshold value before net-energy-producing operation of a reactor becomes possible1,5. 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., Previously documented record values of the fusion triple product in the stellarator Wendelstein 7-X are shown to be evidence for reduced neoclassical energy transport in this optimized device.

Published
2021
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4. Publisher Correction: Demonstration of reduced neoclassical energy transport in Wendelstein 7-X

Author

Beidler, C. D., Smith, H. M., Alonso, A., Andreeva, T., Baldzuhn, J., Beurskens, M. N. A., Borchardt, M., Bozhenkov, S. A., Brunner, K. J., Damm, H., Drevlak, M., Ford, O. P., Fuchert, G., Geiger, J., Helander, P., Hergenhahn, U., Hirsch, M., H��fel, U., Kazakov, Ye. O., Kleiber, R., Krychowiak, M., Kwak, S., Langenberg, A., Laqua, H. P., Neuner, U., Pablant, N. A., Pasch, E., Pavone, A., Pedersen, T. S., Rahbarnia, K., Schilling, J., Scott, E. R., Stange, T., Svensson, J., Thomsen, H., Turkin, Y., Warmer, F., Wolf, R. C., Zhang, D., Abramovic, I., ��k��slompolo, S., Alcus��n, J., Aleynikov, P., Aleynikova, K., Ali, A., Anda, G., Ascasibar, E., B��hner, J. P., Baek, S. G., Balden, M., Banduch, M., Barbui, T., Behr, W., Benndorf, A., Biedermann, C., Biel, W., Blackwell, B., Blanco, E., Blatzheim, M., Ballinger, S., Bluhm, T., B��ckenhoff, D., B��swirth, B., B��ttger, L.-G., Borsuk, V., Boscary, J., Bosch, H.-S., Brakel, R., Brand, H., Brandt, C., Br��uer, T., Braune, H., Brezinsek, S., Brunner, K.-J., Burhenn, R., Bussiahn, R., Buttensch��n, B., Bykov, V., Cai, J., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chaudhary, N., Chauvin, D., Chernyshev, F., Cianciosa, M., Citarella, R., Claps, G., Coenen, J., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czerski, K., Czerwinski, M., Czymek, G., Da Molin, A., Da Silva, A., De La Pena, A., Degenkolbe, S., Dhard, C. P., Dibon, M., Dinklage, A., Dittmar, T., Drewelow, P., Drews, P., Durodie, F., Edlund, E., Effenberg, F., Ehrke, G., Elgeti, S., Endler, M., Ennis, D., Esteban, H., Estrada, T., Fellinger, J., Feng, Y., Flom, E., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Fornal, T., Frerichs, H., Freund, A., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., Garc��a Rega��a, J., Gates, D., Geiger, B., Giannella, V., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Greuner, H., Grosman, A., Grote, H., Gruca, M., Grulke, O., Guerard, C., Hacker, P., Han, X., Harris, J. H., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Henneberg, S., Henkel, M., Hernandez Sanchez, J., Hidalgo, C., Hollfeld, K. P., H��lting, A., H��schen, D., Houry, M., Howard, J., Huang, X., Huang, Z., Hubeny, M., Huber, M., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Jablonski, S., Jakubowski, M., Jelonnek, J., Jenzsch, H., Jesche, T., Jia, M., Junghanns, P., Kacmarczyk, J., Kallmeyer, J.-P., Kamionka, U., Kasahara, H., Kasparek, W., Kenmochi, N., Killer, C., Kirschner, A., Klinger, T., Knauer, J., Knaup, M., Knieps, A., Kobarg, T., Kocsis, G., K��chl, F., Kolesnichenko, Y., K��nies, A., K��nig, R., Kornejew, P., Koschinsky, J.-P., K��ster, F., Kr��mer, M., Krampitz, R., Kr��mer-Flecken, A., Krawczyk, N., Kremeyer, T., Krom, J., Ksiazek, I., Kubkowska, M., K��hner, G., Kurki-Suonio, T., Kurz, P. A., Landreman, M., Lang, P., Lang, R., Langish, S., Laqua, H., Laube, R., Lazerson, S., Lechte, C., Lennartz, M., Leonhardt, W., Li, C., Li, Y., Liang, Y., Linsmeier, C., Liu, S., Lobsien, J.-F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., L��cke, A., Lumsdaine, A., Lutsenko, V., Maa��berg, H., Marchuk, O., Matthew, J. H., Marsen, S., Marushchenko, M., Masuzaki, S., Maurer, D., Mayer, M., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, P., Mikkelsen, D., Mishchenko, A., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., M��nnich, T., Morisaki, T., Moseev, D., Murakami, S., N��fr��di, G., Nagel, M., Naujoks, D., Neilson, H., Neu, R., Neubauer, O., Ngo, T., Nicolai, D., Nielsen, S. K., Niemann, H., Nishizawa, T., Nocentini, R., N��hrenberg, C., N��hrenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., ��lmanns, J., Ongena, J., Oosterbeek, J. W., Orozco, G., Otte, M., Pacios Rodriguez, L., Panadero, N., Panadero Alvarez, N., Papenfu��, D., Paqay, S., Pawelec, E., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., P��l��skei, P., Porkolab, M., Proll, J., Puiatti, M.-E., Puig Sitjes, A., Purps, F., Rack, M., R��csei, S., Reiman, A., Reimold, F., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Risse, K., Rohde, V., R��hlinger, H., Rom��, M., Rondeshagen, D., Rong, P., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Salewski, M., Samartsev, A., S��nchez, E., Sano, F., Satake, S., Schacht, J., Satheeswaran, G., Schauer, F., Scherer, T., Schlaich, A., Schlisio, G., Schluck, F., Schl��ter, K.-H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, P., Schrittwieser, R., Schr��der, M., Schr��der, T., Schroeder, R., Schumacher, H., Schweer, B., Sereda, S., Shanahan, B., Sibilia, M., Sinha, P., Sipli��, S., Slaby, C., Sleczka, M., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Stejner, M., Stephey, L., Stridde, U., Suzuki, C., Szab��, V., Szabolics, T., Szepesi, T., Sz��kefalvi-Nagy, Z., Tamura, N., Tancetti, A., Terry, J., Thomas, J., Thumm, M., Travere, J. M., Traverso, P., Tretter, J., Trimino Mora, H., Tsuchiya, H., Tsujimura, T., Tulip��n, S., Unterberg, B., Vakulchyk, I., Valet, S., Van��, L., Van Eeten, P., Van Milligen, B., Van Vuuren, A. J., Vela, L., Velasco, J.-L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Von Stechow, A., Vork��per, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Wang, Z., Wauters, T., Wegener, L., Weggen, J., Wegner, T., Wei, Y., Weir, G., Wendorf, J., Wenzel, U., Werner, A., White, A., Wiegel, B., Wilde, F., Windisch, T., Winkler, M., Winter, A., Winters, V., Wolf, S., Wright, A., Wurden, G., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zanini, M., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zocco, A., Zoletnik, S., and Zuin, M.

Subjects
Chemical engineering, ddc:660
Published
2021

5. Stray radiation energy fluxes in ITER based on a multiresonator model

Author

Moseev, D., Oosterbeek, J. W., Sirinelli, A., Corre, Y., Houry, M., Korsholm, S. B., Laqua, H. P., Marsen, S., Preynas, M., Rasmussen, J., Salewski, M., Stange, T., Udintsev, V., Moseev, D., Oosterbeek, J. W., Sirinelli, A., Corre, Y., Houry, M., Korsholm, S. B., Laqua, H. P., Marsen, S., Preynas, M., Rasmussen, J., Salewski, M., Stange, T., and Udintsev, V.

Abstract

Here we re-evaluate the stray radiation loads due to electron cyclotron resonance heating and diagnostic gyrotrons in ITER, as well as compute the stray radiation energy flux due to electron cyclotron emission. Microwave loads due to stray radiation were assessed in the past. We give here more comprehensive estimates, including spatial variations in the machine. We show that for the start-up phase in the First Plasma campaign the threshold of 100 kW/m2, which diagnostics have to be able to withstand, is not exceeded. For the later campaigns, the stray radiation energy flux during start-up and burnthrough will exceed 450 kW/m2. Stray radiation from electron cyclotron emission and from a diagnostic 60 GHz gyrotron can contribute to more than 140 kW/m2 combined.

Published
2021

7. Performance of Wendelstein 7-X stellarator plasmas during the first divertor operation phase

Author

Wolf, R. C., Alonso, A., Akaslompolo, S., Baldzuhn, J., Beurskens, M., Beidler, C. D., Biedermann, C., Bosch, H. -S., Bozhenkov, S., Brakel, R., Braune, H., Brezinsek, S., Brunner, K. -J., Damm, H., Dinklage, A., Drewelow, P., Effenberg, F., Feng, Y., Ford, O., Fuchert, G., Gao, Y., Geiger, J., Grulke, O., Harder, N., Hartmann, D., Helander, P., Heinemann, B., Hirsch, M., Hofel, U., Hopf, C., Ida, K., Isobe, M., Jakubowski, M. W., Kazakov, Y. O., Killer, C., Klinger, T., Knauer, J., Konig, R., Krychowiak, M., Langenberg, A., Laqua, H. P., Lazerson, S., Mcneely, P., Marsen, S., Marushchenko, N., Nocentini, R., Ogawa, K., Orozco, G., Osakabe, M., Otte, M., Pablant, N., Pasch, E., Pavone, A., Porkolab, M., Puig Sitjes, A., Rahbarnia, K., Riedl, R., Rust, N., Scott, E., Schilling, J., Schroeder, R., Stange, T., Von Stechow, A., Strumberger, E., Sunn Pedersen, T., Svensson, J., Thomson, H., Turkin, Y., Vano, L., Wauters, T., Wurden, G., Yoshinuma, M., Zanini, M., Zhang, D., Andreeva, T., Brandt, C., Burhenn, R., Buttenschon, B., Geiger, B., Tamura, N., Thomsen, H., Wegner, T., Abramovic, I., Alcuson, J., Aleynikov, P., Aleynikova, K., Ali, A., Anda, G., Ascasibar, E., Bahner, J. P., Baek, S. G., Balden, M., Banduch, M., Barbui, T., Behr, W., Beidler, C., Benndorf, A., Biel, W., Blackwell, B., Blanco, E., Blatzheim, M., Ballinger, S., Bluhm, T., Bockenhoff, D., Boswirth, B., Bottger, L. -G., Borchardt, M., Borsuk, V., Boscary, J., Brand, H., Brauer, T., Bussiahn, R., Bykov, V., Cai, J., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carralero, D., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chaudhary, N., Chauvin, D., Chernyshev, F., Cianciosa, M., Citarella, R., Claps, G., Coenen, J., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czerski, K., Czerwinski, M., Czymek, G., Da Molin, A., Da Silva, A., De La Pena, A., Degenkolbe, S., Dhard, C. P., Dibon, M., Dittmar, T., Drevlak, M., Drews, P., Durodie, F., Edlund, E., Van Eeten, P., Ehrke, G., Elgeti, S., Endler, M., Ennis, D., Esteban, H., Estrada, T., Fellinger, J., Flom, E., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Fornal, T., Frerichs, H., Freund, A., Funaba, T., Galkowski, A., Gantenbein, G., Garcia Regana, J., Gates, D., Giannella, V., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Greuner, H., Grosman, A., Grote, H., Gruca, M., Guerard, C., Hacker, P., Han, X., Harris, J. H., Hathiramani, D., Hein, B., Henneberg, S., Henkel, M., Hernandez Sanchez, J., Hidalgo, C., Hollfeld, K. P., Holting, A., Hoschen, D., Houry, M., Howard, J., Huang, X., Huang, Z., Hubeny, M., Huber, M., Hunger, H., Ilkei, T., Illy, S., Israeli, B., Jablonski, S., Jakubowski, M., Jelonnek, J., Jenzsch, H., Jesche, T., Jia, M., Junghanns, P., Kacmarczyk, J., Kallmeyer, J. -P., Kamionka, U., Kasahara, H., Kasparek, W., Kenmochi, N., Kirschner, A., Kleiber, R., Knaup, M., Knieps, A., Kobarg, T., Kocsis, G., Kochl, F., Kolesnichenko, Y., Konies, A., Kornejew, P., Koschinsky, J. -P., Koster, F., Kramer, M., Krampitz, R., Kramer-Flecken, A., Krawczyk, N., Kremeyer, T., Krom, J., Ksiazek, I., Kubkowska, M., Kuhner, G., Kurki-Suonio, T., Kurz, P. A., Kwak, S., Landreman, M., Lang, P., Lang, R., Langish, S., Laqua, H., Laube, R., Lechte, C., Lennartz, M., Leonhardt, W., Li, C., Li, Y., Liang, Y., Linsmeier, C., Liu, S., Lobsien, J. -F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., Lucke, A., Lumsdaine, A., Lutsenko, V., Maassberg, H., Marchuk, O., Matthew, J. H., Marushchenko, M., Masuzaki, S., Maurer, D., Mayer, M., Mccarthy, K., Meier, A., Mellein, D., Mendelevitch, B., Mertens, P., Mikkelsen, D., Mishchenko, A., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., Monnich, T., Morisaki, T., Moseev, D., Murakami, S., Nafradi, G., Nagel, M., Naujoks, D., Neilson, H., Neu, R., Neubauer, O., Neuner, U., Ngo, T., Nicolai, D., Nielsen, S. K., Niemann, H., Nishizawa, T., Nuhrenberg, C., Nuhrenberg, J., Obermayer, S., Offermanns, G., Olmanns, J., Ongena, J., Oosterbeek, J. W., Pacios Rodriguez, L., Panadero, N., Panadero Alvarez, N., Papenfuss, D., Paqay, S., Pawelec, E., Pedersen, T. S., Pelka, G., Perseo, V., Peterson, B., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., Poloskei, P., Proll, J., Puiatti, M. -E., Purps, F., Rack, M., Recsei, S., Reiman, A., Reimold, F., Reiter, D., Remppel, F., Renard, S., Riemann, J., Risse, K., Rohde, V., Rohlinger, H., Rome, M., Rondeshagen, D., Rong, P., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Ryc, L., Ryosuke, S., Sakamoto, R., Salewski, M., Samartsev, A., Sanchez, E., Sano, F., Satake, S., Schacht, J., Satheeswaran, G., Schauer, F., Scherer, T., Schlaich, A., Schlisio, G., Schluck, F., Schluter, K. -H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, P., Schrittwieser, R., Schroder, M., Schroder, T., Schumacher, H., Schweer, B., Sereda, S., Shanahan, B., Sibilia, M., Sinha, P., Siplia, S., Slaby, C., Sleczka, M., Smith, H., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Stejner, M., Stephey, L., Stridde, U., Suzuki, C., Szabo, V., Szabolics, T., Szepesi, T., Szokefalvi-Nagy, Z., Tancetti, A., Terry, J., Thomas, J., Thumm, M., Travere, J. M., Traverso, P., Tretter, J., Trimino Mora, H., Tsuchiya, H., Tsujimura, T., Tulipan, S., Unterberg, B., Vakulchyk, I., Valet, S., Van Milligen, B., Van Vuuren, A. J., Vela, L., Velasco, J. -L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Vorkoper, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Wang, Z., Warmer, F., Wegener, L., Weggen, J., Wei, Y., Weir, G., Wendorf, J., Wenzel, U., Werner, A., White, A., Wiegel, B., Wilde, F., Windisch, T., Winkler, M., Winter, A., Winters, V., Wolf, S., Wright, A., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zocco, A., Zoletnik, S., Zuin, M., Science and Technology of Nuclear Fusion, Turbulence in Fusion Plasmas, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Physics, Technology, Plasma parameters, Divertor, Nuclear engineering, Plasma, Condensed Matter Physics, 01 natural sciences, 7. Clean energy, Electron cyclotron resonance, 010305 fluids & plasmas, law.invention, Magnetic field, law, 0103 physical sciences, Limiter, Wendelstein 7-X, 010306 general physics, ddc:600, Stellarator
Abstract

Wendelstein 7-X is the first comprehensively optimized stellarator aiming at good confinement with plasma parameters relevant to a future stellarator power plant. Plasma operation started in 2015 using a limiter configuration. After installing an uncooled magnetic island divertor, extending the energy limit from 4 to 80 MJ, operation continued in 2017. For this phase, the electron cyclotron resonance heating (ECRH) capability was extended to 7 MW, and hydrogen pellet injection was implemented. The enhancements resulted in the highest triple product (6.5 × 1019 keV m-3 s) achieved in a stellarator until now. Plasma conditions [Te(0) ≈ Ti(0) ≈ 3.8 keV, τE > 200 ms] already were in the stellarator reactor-relevant ion-root plasma transport regime. Stable operation above the 2nd harmonic ECRH X-mode cutoff was demonstrated, which is instrumental for achieving high plasma densities in Wendelstein 7-X. Further important developments include the confirmation of low intrinsic error fields, the observation of current-drive induced instabilities, and first fast ion heating and confinement experiments. The efficacy of the magnetic island divertor was instrumental in achieving high performance in Wendelstein 7-X. Symmetrization of the heat loads between the ten divertor modules could be achieved by external resonant magnetic fields. Full divertor power detachment facilitated the extension of high power plasmas significantly beyond the energy limit of 80 MJ.

Published
2019
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8. Major results from the first plasma campaign of the Wendelstein 7-X stellarator

Author

Wolf, R.C., Ali, A., Alonso, A., Baldzuhn, J., Beidler, C., Beurskens, M., Biedermann, C., Bosch, H.S., Bozhenkov, S., Brakel, R., Dinklage, A., Feng, Y., Fuchert, G., Geiger, J., Grulke, O., Helander, P., Hirsch, M., Höfel, U., Jakubowski, M., Knauer, J., Kocsis, G., König, R., Kornejew, P., Kràmer-Flecken, A., Krychowiak, M., Landreman, M., Langenberg, A., Laqua, H. P., Lazerson, S., Maaßberg, H., Marsen, S., Marushchenko, M., Moseev, D., Niemann, H., Pablant, N., Pasch, E., Rahbarnia, K., Schlisio, G., Stange, T., Sunn Pedersen, T., Svensson, J., Szepesi, T., Trimino Mora, H., Turkin, Y., Wauters, T., Weir, G., Wenzel, U., Windisch, T., Wurden, G., Zhang, D., Abramovic, I., Äkàslompolo, S., Aleynikov, P., Aleynikova, K., Alzbutas, R., Anda, G., Andreeva, T., Ascasibar, E., Assmann, J., Baek, S. G., Banduch, M., Barbui, T., Barlak, M., Baumann, K., Behr, W., Benndorf, A., Bertuch, O., Biel, W., Birus, D., Blackwell, B., Blanco, E., Blatzheim, M., Bluhm, T., Böckenhoff, D., Bolgert, P., Borchardt, M., Borsuk, V., Boscary, J., Böttger, L. G., Brand, H., Brandt, Ch, Bràuer, T., Braune, H., Brezinsek, S., Brunner, K. J., Brünner, B., Burhenn, R., Buttenschön, B., Bykov, V., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chernyshev, F., Cianciosa, M., Citarella, R., Ciupiński, Claps, G., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czermak, A., Czerski, K., Czerwinski, M., Czymek, G., Da Molin, A., Da Silva, A., Dammertz, G., Danielson, J., De La Pena, A., Degenkolbe, S., Denner, P., Dhard, D. P., Dostal, M., Drevlak, M., Drewelow, P., Drews, Ph, Dudek, A., Dundulis, G., Durodie, F., Van Eeten, P., Effenberg, F., Ehrke, G., Endler, M., Ennis, D., Erckmann, E., Esteban, H., Estrada, T., Fahrenkamp, N., Feist, J. H., Fellinger, J., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Ford, O., Fornal, T., Frerichs, H., Freund, A., Führer, M., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., García Regaña, J., Garcia-Munoz, M., Gates, D., Gawlik, G., Geiger, B., Giannella, V., Gierse, N., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Grosman, A., Grote, H., Gruca, M., Guerard, C., Haiduk, L., Han, X., Harberts, F., Harris, J. H., Hartfuß, H. J., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Heitzenroeder, P., Henneberg, S., Hennig, C., Hernandez Sanchez, J., Hidalgo, C., Hölbe, H., Hollfeld, K. P., Hölting, A., Höschen, D., Houry, M., Howard, J., Huang, X., Huber, M., Huber, V., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Ivanov, A., Jablonski, S., Jagielski, J., Jelonnek, J., Jenzsch, H., Junghans, P., Kacmarczyk, J., Kaliatka, T., Kallmeyer, J. P., Kamionka, U., Karalevicius, R., Kasahara, H., Kasparek, W., Kenmochi, N., Keunecke, M., Khilchenko, A., Kinna, D., Kleiber, R., Klinger, T., Knaup, M., Kobarg, Th, Köchl, F., Kolesnichenko, Y., Könies, A., Köppen, M., Koshurinov, J., Koslowski, R., Köster, F., Koziol, R., Krämer, M., Krampitz, R., Kraszewsk, P., Krawczyk, N., Kremeyer, T., Krings, Th, Krom, J., Krzesinski, G., Ksiazek, I., Kubkowska, M., Kühner, G., Kurki-Suonio, T., Kwak, S., Lang, R., Langish, S., Laube, R., Lechte, C., Lennartz, M., Leonhardt, W., Lewerentz, L., Liang, Y., Linsmeier, Ch, Liu, S., Lobsien, J. F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., Lubyako, L., Lücke, A., Lumsdaine, A., Lutsenko, V., Majano-Brown, J., Marchuk, O., Mardenfeld, M., Marek, P., Massidda, S., Masuzaki, S., Maurer, D., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, Ph, Mikkelsen, D., Mishchenko, O., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., Mönnich, T., Morizaki, T., Munk, R., Murakami, S., Musielok, F., Náfrádi, G., Nagel, M., Naujoks, D., Neilson, H., Neubauer, O., Neuner, U., Ngo, T., Nocentini, R., Nührenberg, C., Nührenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., Ongena, J., Oosterbeek, J. W., Orozco, G., Otte, M., Pacios Rodriguez, L., Pan, W., Panadero, N., Panadero Alvarez, N., Panin, A., Papenfuß, D., Paqay, S., Pavone, A., Pawelec, E., Pelka, G., Peng, X., Perseo, V., Peterson, B., Pieper, A., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., Povilaitis, M., Preinhaelter, J., Proll, J., Puiatti, M. E., Puig Sitjes, A., Purps, F., Rack, M., Récsei, S., Reiman, A., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Rimkevicius, S., Riße, K., Rodatos, A., Röhlinger, H., Romé, M., Rong, P., Roscher, H. J., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Samartsev, A., Sanchez, M., Sano, F., Satake, S., Satheeswaran, G., Schacht, J., Schauer, F., Scherer, T., Schlaich, A., Schlüter, K. H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, M., Scholz, P., Schrittwieser, R., Schröder, M., Schröder, T., Schroeder, R., Schumacher, H., Schweer, B., Shanahan, B., Shikhovtsev, I. V., Sibilia, M., Sinha, P., Siplià, S., Skodzik, J., Slaby, C., Smith, H., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Standley, B., Stephey, L., Stoneking, M., Stridde, U., Sulek, Z., Surko, C., Suzuki, Y., Szabó, V., Szabolics, T., Szökefalvi-Nagy, Z., Tamura, N., Terra, A., Terry, J., Thomas, J., Thomsen, H., Thumm, M., Von Thun, C. P., Timmermann, D., Titus, P., Toi, K., Travere, J. M., Traverso, P., Tretter, J., Tsuchiya, H., Tsujimura, T., Tulipán, S., Turnyanskiy, M., Unterberg, B., Urban, J., Urbonavicius, E., Vakulchyk, I., Valet, S., Van Millingen, B., Vela, L., Velasco, J. L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Vorkörper, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Warmer, F., Wegener, L., Weggen, J., Wei, Y., Wendorf, J., Werner, A., Wiegel, B., Wilde, F., Winkler, E., Winters, V., Wolf, S., Wolowski, J., Wright, A., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zajac, J., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zimbal, A., Zocco, A., Zoletnik, S., Zuin, M., Wolf, R.C., Ali, A., Alonso, A., Baldzuhn, J., Beidler, C., Beurskens, M., Biedermann, C., Bosch, H.S., Bozhenkov, S., Brakel, R., Dinklage, A., Feng, Y., Fuchert, G., Geiger, J., Grulke, O., Helander, P., Hirsch, M., Höfel, U., Jakubowski, M., Knauer, J., Kocsis, G., König, R., Kornejew, P., Kràmer-Flecken, A., Krychowiak, M., Landreman, M., Langenberg, A., Laqua, H. P., Lazerson, S., Maaßberg, H., Marsen, S., Marushchenko, M., Moseev, D., Niemann, H., Pablant, N., Pasch, E., Rahbarnia, K., Schlisio, G., Stange, T., Sunn Pedersen, T., Svensson, J., Szepesi, T., Trimino Mora, H., Turkin, Y., Wauters, T., Weir, G., Wenzel, U., Windisch, T., Wurden, G., Zhang, D., Abramovic, I., Äkàslompolo, S., Aleynikov, P., Aleynikova, K., Alzbutas, R., Anda, G., Andreeva, T., Ascasibar, E., Assmann, J., Baek, S. G., Banduch, M., Barbui, T., Barlak, M., Baumann, K., Behr, W., Benndorf, A., Bertuch, O., Biel, W., Birus, D., Blackwell, B., Blanco, E., Blatzheim, M., Bluhm, T., Böckenhoff, D., Bolgert, P., Borchardt, M., Borsuk, V., Boscary, J., Böttger, L. G., Brand, H., Brandt, Ch, Bràuer, T., Braune, H., Brezinsek, S., Brunner, K. J., Brünner, B., Burhenn, R., Buttenschön, B., Bykov, V., Calvo, I., Cannas, B., Cappa, A., Carls, A., Carraro, L., Carvalho, B., Castejon, F., Charl, A., Chernyshev, F., Cianciosa, M., Citarella, R., Ciupiński, Claps, G., Cole, M., Cole, M. J., Cordella, F., Cseh, G., Czarnecka, A., Czermak, A., Czerski, K., Czerwinski, M., Czymek, G., Da Molin, A., Da Silva, A., Dammertz, G., Danielson, J., De La Pena, A., Degenkolbe, S., Denner, P., Dhard, D. P., Dostal, M., Drevlak, M., Drewelow, P., Drews, Ph, Dudek, A., Dundulis, G., Durodie, F., Van Eeten, P., Effenberg, F., Ehrke, G., Endler, M., Ennis, D., Erckmann, E., Esteban, H., Estrada, T., Fahrenkamp, N., Feist, J. H., Fellinger, J., Fernandes, H., Fietz, W. H., Figacz, W., Fontdecaba, J., Ford, O., Fornal, T., Frerichs, H., Freund, A., Führer, M., Funaba, T., Galkowski, A., Gantenbein, G., Gao, Y., García Regaña, J., Garcia-Munoz, M., Gates, D., Gawlik, G., Geiger, B., Giannella, V., Gierse, N., Gogoleva, A., Goncalves, B., Goriaev, A., Gradic, D., Grahl, M., Green, J., Grosman, A., Grote, H., Gruca, M., Guerard, C., Haiduk, L., Han, X., Harberts, F., Harris, J. H., Hartfuß, H. J., Hartmann, D., Hathiramani, D., Hein, B., Heinemann, B., Heitzenroeder, P., Henneberg, S., Hennig, C., Hernandez Sanchez, J., Hidalgo, C., Hölbe, H., Hollfeld, K. P., Hölting, A., Höschen, D., Houry, M., Howard, J., Huang, X., Huber, M., Huber, V., Hunger, H., Ida, K., Ilkei, T., Illy, S., Israeli, B., Ivanov, A., Jablonski, S., Jagielski, J., Jelonnek, J., Jenzsch, H., Junghans, P., Kacmarczyk, J., Kaliatka, T., Kallmeyer, J. P., Kamionka, U., Karalevicius, R., Kasahara, H., Kasparek, W., Kenmochi, N., Keunecke, M., Khilchenko, A., Kinna, D., Kleiber, R., Klinger, T., Knaup, M., Kobarg, Th, Köchl, F., Kolesnichenko, Y., Könies, A., Köppen, M., Koshurinov, J., Koslowski, R., Köster, F., Koziol, R., Krämer, M., Krampitz, R., Kraszewsk, P., Krawczyk, N., Kremeyer, T., Krings, Th, Krom, J., Krzesinski, G., Ksiazek, I., Kubkowska, M., Kühner, G., Kurki-Suonio, T., Kwak, S., Lang, R., Langish, S., Laube, R., Lechte, C., Lennartz, M., Leonhardt, W., Lewerentz, L., Liang, Y., Linsmeier, Ch, Liu, S., Lobsien, J. F., Loesser, D., Loizu Cisquella, J., Lore, J., Lorenz, A., Losert, M., Lubyako, L., Lücke, A., Lumsdaine, A., Lutsenko, V., Majano-Brown, J., Marchuk, O., Mardenfeld, M., Marek, P., Massidda, S., Masuzaki, S., Maurer, D., McCarthy, K., McNeely, P., Meier, A., Mellein, D., Mendelevitch, B., Mertens, Ph, Mikkelsen, D., Mishchenko, O., Missal, B., Mittelstaedt, J., Mizuuchi, T., Mollen, A., Moncada, V., Mönnich, T., Morizaki, T., Munk, R., Murakami, S., Musielok, F., Náfrádi, G., Nagel, M., Naujoks, D., Neilson, H., Neubauer, O., Neuner, U., Ngo, T., Nocentini, R., Nührenberg, C., Nührenberg, J., Obermayer, S., Offermanns, G., Ogawa, K., Ongena, J., Oosterbeek, J. W., Orozco, G., Otte, M., Pacios Rodriguez, L., Pan, W., Panadero, N., Panadero Alvarez, N., Panin, A., Papenfuß, D., Paqay, S., Pavone, A., Pawelec, E., Pelka, G., Peng, X., Perseo, V., Peterson, B., Pieper, A., Pilopp, D., Pingel, S., Pisano, F., Plaum, B., Plunk, G., Povilaitis, M., Preinhaelter, J., Proll, J., Puiatti, M. E., Puig Sitjes, A., Purps, F., Rack, M., Récsei, S., Reiman, A., Reiter, D., Remppel, F., Renard, S., Riedl, R., Riemann, J., Rimkevicius, S., Riße, K., Rodatos, A., Röhlinger, H., Romé, M., Rong, P., Roscher, H. J., Roth, B., Rudischhauser, L., Rummel, K., Rummel, T., Runov, A., Rust, N., Ryc, L., Ryosuke, S., Sakamoto, R., Samartsev, A., Sanchez, M., Sano, F., Satake, S., Satheeswaran, G., Schacht, J., Schauer, F., Scherer, T., Schlaich, A., Schlüter, K. H., Schmitt, J., Schmitz, H., Schmitz, O., Schmuck, S., Schneider, M., Schneider, W., Scholz, M., Scholz, P., Schrittwieser, R., Schröder, M., Schröder, T., Schroeder, R., Schumacher, H., Schweer, B., Shanahan, B., Shikhovtsev, I. V., Sibilia, M., Sinha, P., Siplià, S., Skodzik, J., Slaby, C., Smith, H., Spiess, W., Spong, D. A., Spring, A., Stadler, R., Standley, B., Stephey, L., Stoneking, M., Stridde, U., Sulek, Z., Surko, C., Suzuki, Y., Szabó, V., Szabolics, T., Szökefalvi-Nagy, Z., Tamura, N., Terra, A., Terry, J., Thomas, J., Thomsen, H., Thumm, M., Von Thun, C. P., Timmermann, D., Titus, P., Toi, K., Travere, J. M., Traverso, P., Tretter, J., Tsuchiya, H., Tsujimura, T., Tulipán, S., Turnyanskiy, M., Unterberg, B., Urban, J., Urbonavicius, E., Vakulchyk, I., Valet, S., Van Millingen, B., Vela, L., Velasco, J. L., Vergote, M., Vervier, M., Vianello, N., Viebke, H., Vilbrandt, R., Vorkörper, A., Wadle, S., Wagner, F., Wang, E., Wang, N., Warmer, F., Wegener, L., Weggen, J., Wei, Y., Wendorf, J., Werner, A., Wiegel, B., Wilde, F., Winkler, E., Winters, V., Wolf, S., Wolowski, J., Wright, A., Xanthopoulos, P., Yamada, H., Yamada, I., Yasuhara, R., Yokoyama, M., Zajac, J., Zarnstorff, M., Zeitler, A., Zhang, H., Zhu, J., Zilker, M., Zimbal, A., Zocco, A., Zoletnik, S., and Zuin, M.

Abstract

After completing the main construction phase of Wendelstein 7-X (W7-X) and successfully commissioning the device, first plasma operation started at the end of 2015. Integral commissioning of plasma start-up and operation using electron cyclotron resonance heating (ECRH) and an extensive set of plasma diagnostics have been completed, allowing initial physics studies during the first operational campaign. Both in helium and hydrogen, plasma breakdown was easily achieved. Gaining experience with plasma vessel conditioning, discharge lengths could be extended gradually. Eventually, discharges lasted up to 6 s, reaching an injected energy of 4 MJ, which is twice the limit originally agreed for the limiter configuration employed during the first operational campaign. At power levels of 4 MW central electron densities reached 3 1019 m-3, central electron temperatures reached values of 7 keV and ion temperatures reached just above 2 keV. Important physics studies during this first operational phase include a first assessment of power balance and energy confinement, ECRH power deposition experiments, 2nd harmonic O-mode ECRH using multi-pass absorption, and current drive experiments using electron cyclotron current drive. As in many plasma discharges the electron temperature exceeds the ion temperature significantly, these plasmas are governed by core electron root confinement showing a strong positive electric field in the plasma centre.

Published
2017

10. Feedback control of tearing modes through ECRH with launcher mirror steering and power modulation using a line-of-sight ECE diagnostic

Author

Hennen, B. A., Egbert Westerhof, Nuij, P. W. J. M., Ayten, B., Marco de Baar, Bongers, W. A., Bürger, A., D. Lazzari, De, Oosterbeek, J. W., Thoen, D. J., Maarten Steinbuch, Control Systems Technology, Science and Technology of Nuclear Fusion, and Mechanical Engineering

Abstract

A demonstration of real-time feedback control for autonomous tracking and stabilization of m/n = 2/1 tearing modes in a tokamak using Electron Cyclotron Resonance Heating and Current Drive (ECRH/ECCD) is reported. The prototype system on TEXTOR combines in the same sight-line an Electron Cyclotron Emission (ECE) diagnostic for tearing mode sensing and a steer-able ECRH/ECCD antenna. The mode location is retrieved from the ECE measurements and serves as input for a control loop, which aligns the ECRH/ECCD deposition with the tearing modes by steering of a launcher mirror. The alignment is achieved by matching the mode location in the sensor spectrum with the fixed ECRH/ECCD actuator frequency. The control response is dominated by the response of the mechanical launcher. Analysis of the launcher dynamics receives special emphasis in the control design. In addition, the ECRH/ECCD power is modulated in phase with the rotation frequency of the O-point of the tearing modes using a feedback loop, which extracts the modes frequency and phase from the ECE data. The 'line-of-sight' concept has advantages over conventional tearing mode suppression schemes as it provides information of the modes location and phase in the direct vicinity of the EC-deposition. It avoids the use of ray-tracing in the control loop and guarantees accurate alignment in the presence of disturbances. The experimental results demonstrate the capabilities of the control system to track and suppress tearing modes in real-time. A relatively simple control design suffices to meet the performance requirements demanded for effective tearing mode suppression. In addition, a control-oriented model for the tearing mode control problem is being developed. This model includes tearing mode and plasma dynamics, models for the actuators, diagnostics, data-processing and control algorithms. Simulation results for typical TEXTOR conditions will be discussed and validated with experimental results.

Published
2010

12. Fast ion dynamics in TEXTOR measured by collective Thomson scattering

Author

Bindslev, H., Nielsen, S. K., Westerhof, E., Woskov, P., TEXTOR, Team., Porte, L., Hoekzema, J. A., Korsholm, S. B., Meo, F., Michelsen, P. K., Michelsen, S., Oosterbeek, J. W., and Tsakadze, E. L.

Subjects
Physics::Plasma Physics, ddc:550
Abstract

Here we present the first measurements by collective Thomson scattering of the evolution of fast-ion populations in a magnetically confined fusion plasma. 150 kW and 110 Ghz radiation from a gyrotron were scattered in the TEXTOR tokamak plasma with energetic ions generated by neutral beam injection and ion cyclotron resonance heating. The temporal behavior of the spatially resolved fast-ion velocity distribution is inferred from the received scattered radiation. The fast-ion dynamics at sawteeth and the slowdown after switch off of auxiliary heating is resolved in time. The latter is shown to be in close agreement with modeling results.

Published
2006
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15. Engineering aspects of microwave diagnostics in ITER

Author

Patel, K. M., primary, Udintsev, V. S., additional, Vayakis, G., additional, Giacomin, T., additional, Johnson, D., additional, Maquet, Ph., additional, Pandya, H. K. B., additional, Penot, C., additional, Portales, M., additional, Proust, M., additional, Oosterbeek, J. W., additional, Vershkov, V., additional, and Walsh, M. J., additional

Published
2014
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16. Experimental characterization of anomalous strong scattering of mm-waves in TEXTOR plasmas with rotating islands

Author

Nielsen, Stefan Kragh, Salewski, Mirko, Westerhof, E, Bongers, W, Korsholm, Søren Bang, Leipold, Frank, Oosterbeek, J W, Moseev, D, Stejner Pedersen, Morten, Nielsen, Stefan Kragh, Salewski, Mirko, Westerhof, E, Bongers, W, Korsholm, Søren Bang, Leipold, Frank, Oosterbeek, J W, Moseev, D, and Stejner Pedersen, Morten

Abstract

Anomalous scattering of high power millimetre waves from gyrotrons at 140 and 110 GHz is investigated for plasma with rotating islands at TEXTOR. The magnetic field and plasma density influence the spectral content of the scattered waves and their power levels significantly. Anomalous strong scattering occurs in two density regimes, one at low densities and one at high densities, that also depend on the magnetic field. The two regimes are separated by a quiescent regime without anomalous scattering. Investigations suggest that scattering in the high-density regime is generated at the low-field side intersection of the gyrotron beam and the island position. The transition from the quiescent regime to the high-density regime occurs when the gyrotron frequency is twice the upper hybrid frequency at this position. There is some evidence that the scattering in the low-density regime is generated near the plasma centre. Under this assumption all the observed scattering is generated when the gyrotron frequency is near or below twice the upper hybrid frequency.

Published
2013

18. Diagnostics development for quasi-steady-state operation of the Wendelstein 7-X stellarator (invited)

Author

König, R., primary, Baldzuhn, J., additional, Biedermann, C., additional, Burhenn, R., additional, Bozhenkov, S., additional, Cardella, A., additional, Endler, M., additional, Hartfuss, H.-J., additional, Hathiramani, D., additional, Hildebrandt, D., additional, Hirsch, M., additional, Jakubowski, M., additional, Kocsis, G., additional, Kornejev, P., additional, Krychowiak, M., additional, Laqua, H. P., additional, Laux, M., additional, Oosterbeek, J. W., additional, Pasch, E., additional, Richert, T., additional, Schneider, W., additional, Sunn-Pedersen, T., additional, Thomsen, H., additional, Weller, A., additional, Werner, A., additional, Wolf, R., additional, Zhang, D., additional, and Zoletnik, S., additional

Published
2012
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19. Diagnostics design for steady-state operation of the Wendelstein 7-X stellarator

Author

König, R., primary, Baldzuhn, J., additional, Biel, W., additional, Biedermann, C., additional, Burhenn, R., additional, Bozhenkov, S., additional, Cantarini, J., additional, Dreier, H., additional, Endler, M., additional, Hartfuss, H.-J., additional, Hildebrandt, D., additional, Hirsch, M., additional, Jakubowski, M., additional, Jimenez-Gomez, R., additional, Kocsis, G., additional, Kornejev, P., additional, Krychowiak, M., additional, Laqua, H. P., additional, Laux, M., additional, Oosterbeek, J. W., additional, Pasch, E., additional, Richert, T., additional, Schneider, W., additional, Schweer, B., additional, Svensson, J., additional, Thomsen, H., additional, Weller, A., additional, Werner, A., additional, Wolf, R., additional, Zhang, D., additional, and Zoletnik, S., additional

Published
2010
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21. Utilization of collinear ECE detection/ECRH heating for active stabilization of plasma instabilities

Author

Bongers, W. A., primary, Kasparek, W., additional, Donne, A. J. H., additional, Goede, A. P. H., additional, de Baar, M. R., additional, Schuller, F. C., additional, Erckmann, V., additional, Stober, J., additional, Westerhof, E., additional, Amerongen, F. J., additional, Hennen, B. A., additional, Nuij, P. W. J. M., additional, Oosterbeek, J. W., additional, Ronden, D. M. S., additional, Thoen, D. J., additional, Tongerlo, T., additional, and Wagner, D., additional

Published
2010
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22. Development and testing of a fast Fourier transform high dynamic-range spectral diagnostics for millimeter wave characterization

Author

Thoen, D. J., primary, Bongers, W. A., additional, Westerhof, E., additional, Oosterbeek, J. W., additional, de Baar, M. R., additional, van den Berg, M. A., additional, van Beveren, V., additional, Bürger, A., additional, Goede, A. P. H., additional, Graswinckel, M. F., additional, Hennen, B. A., additional, and Schüller, F. C., additional

Published
2009
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24. Fast fourier transform based diagnostics for spectral characterization of millimeter waves in tokamaks

Author

Thoen, D. J., primary, Bongers, W. A., additional, Westerhof, E., additional, Oosterbeek, J. W., additional, de Baar, M. R., additional, van den Berg, M. A., additional, van Beveren, V., additional, Burger, A., additional, Goede, A. P. H., additional, Graswinckel, M. F., additional, Hennen, M. F., additional, and Schuller, F. C., additional

Published
2009
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25. Electron Cyclotron Resonance Heating for W7-X

Author

Michel, G., primary, Brand, P., additional, Braune, H., additional, Erckmann, V., additional, Gantenbein, G., additional, Kasparek, W., additional, Laqua, H. P., additional, Marushchenko, N., additional, Oosterbeek, J. W., additional, Thumm, M., additional, Weiβgerber, M., additional, Bobkov, Volodymyr, additional, and Noterdaeme, Jean-Marie, additional

Published
2009
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27. A line-of-sight electron cyclotron emission receiver for electron cyclotron resonance heating feedback control of tearing modes

Author

Oosterbeek, J. W., primary, Bürger, A., additional, Westerhof, E., additional, de Baar, M. R., additional, van den Berg, M. A., additional, Bongers, W. A., additional, Graswinckel, M. F., additional, Hennen, B. A., additional, Kruijt, O. G., additional, Thoen, J., additional, Heidinger, R., additional, Korsholm, S. B., additional, Leipold, F., additional, and Nielsen, S. K., additional

Published
2008
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28. Temporal evolution of confined fast-ion velocity distributions measured by collective Thomson scattering in TEXTOR

Author

Nielsen, S. K., primary, Bindslev, H., additional, Porte, L., additional, Hoekzema, J. A., additional, Korsholm, S. B., additional, Leipold, F., additional, Meo, F., additional, Michelsen, P. K., additional, Michelsen, S., additional, Oosterbeek, J. W., additional, Tsakadze, E. L., additional, Van Wassenhove, G., additional, Westerhof, E., additional, and Woskov, P., additional

Published
2008
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31. Frequency measurements of the gyrotrons used for collective Thomson scattering diagnostics at TEXTOR and ASDEX Upgrade

Author

Woskov, P., primary, Bindslev, H., additional, Leipold, F., additional, Meo, F., additional, Nielsen, S. K., additional, Tsakadze, E. L., additional, Korsholm, S. B., additional, Scholten, J., additional, Tito, C., additional, Westerhof, E., additional, Oosterbeek, J. W., additional, Leuterer, F., additional, Monaco, F., additional, Muenich, M., additional, and Wagner, D., additional

Published
2006
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32. Electron Cyclotron Resonance Heating on TEXTOR

Author

Westerhof, E., primary, Hoekzema, J. A., additional, Hogeweij, G. M. D., additional, Jaspers, R. J. E., additional, Schüller, F. C., additional, Barth, C. J., additional, Bindslev, H., additional, Bongers, W. A., additional, Donné, A. J. H., additional, Dumortier, P., additional, Van Der Grift, A. F., additional, Kalupin, D., additional, Koslowski, H. R., additional, Krämer-Flecken, A., additional, Kruijt, O. G., additional, Cardozo, N. J. Lopes, additional, Van Der Meiden, H. J., additional, Merkulov, A., additional, Messiaen, A., additional, Oosterbeek, J. W., additional, Prins, P. R., additional, Scholten, J., additional, Udintsev, V. S., additional, Unterberg, B., additional, Vervier, M., additional, and Van Wassenhove, G., additional

Published
2005
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35. Electron Cyclotron Resonance Heating for W7-X.

Author

Michel, G., Brand, P., Braune, H., Erckmann, V., Gantenbein, G., Kasparek, W., Laqua, H. P., Marushchenko, N., Oosterbeek, J. W., Thumm, M., and Weißgerber, M.

Subjects
ELECTRON cyclotron resonance sources, ELECTRONS, CYCLOTRONS, HEATING, QUANTUM electrodynamics
Abstract

The HELIAS-type Stellarator Wendelstein 7-X, which is currently under construction in Greifswald, Germany, will be equipped with a 140 GHz, 10 MW, CW ECRH system. It will be the main plasma heating system for W7-X. The key features and capabilities of the ECRH plant will be discussed together with the envisaged start-up and heating scenarios. We also report on the ECRH stray radiation test facility MISTRAL and on the extension of the gyrotron frequency range. [ABSTRACT FROM AUTHOR]

Published
2009
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36. FIRST RESULTS OF THE TEXTOR LINE OF SIGHT ECE SYSTEM FOR ECRH FEEDBACK.

Author

OOSTERBEEK, J. W., BÜRGER, A., HOEKZEMA, J. A., WESTERHOF, E., DE BAAR, M., VAN DEN BERG, M. A., BONGERS, W. A., GRASWINCKEL, M. F., HENNEN, B. A., KRUIJT, O. G., LAMERS, B., THOEN, D. J., VAESSEN, B. C. E., WORTMAN, P. M., HEIDINGER, R., KORSHOLM, S. B., LEIPOLD, F., and NIELSEN, S. K.

Subjects
PLASMA gases, IONIZED gases, PLASMA physics, CYCLOTRON resonance, MAGNETIC resonance
Published
2009

37. The 140 GHz ECW system on TEXTOR.

Author

Hoekzema, J. A., Bongers, W. A., van der Grift, A. F., Kruijt, O. G., Oosterbeek, J. W., Poelman, A. J., Prins, P. R., Scholten, J., Schüller, F. C., Sterk, A. B., Tito, C. J., and Westerhof, E.

Subjects
GYROTRONS, ELECTRIC lines, TOKAMAKS, THOMSON scattering, OPTICAL materials, MASERS
Published
2003

38. The 113 GHz ECRH system for JET.

Author

Verhoeven, A. G. A., Bongers, W. A., Elzendoorn, B. S. Q., Graswincke, M., Hellingman, P., Kamp, J. J., Kooijman, W., Kruijt, O. G., Maagdenberg, J., Ronden, D., Stakenborg, J., Sterk, A. B., Tichler, J., Alberti, S., Goodman, T., Henderson, M., Hoekzema, J. A., Oosterbeek, J. W., Fernandez, A., and Likin, K.

Subjects
ELECTRON cyclotron resonance heating, GYROTRONS, TOROIDAL plasma, OSCILLATIONS, ELECTROMAGNETIC waves
Published
2003

40. First results of collective scattering on JET (invited)

Author

Hoekzema, J. A., primary, Bindslev, H., additional, Egedal, J., additional, Fessey, J. A., additional, Gatcombe, C. P., additional, Hammond, N. P., additional, Hughes, T. P., additional, Machuzak, J. S., additional, Oosterbeek, J. W., additional, Roberts, P. J., additional, Stevens, A. L., additional, and Stott, P. E., additional

Published
1997
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41. Experimental characterization of anomalous strong scattering of mm-waves in TEXTOR plasmas with rotating islands.

Author

Nielsen, S K, Salewski, M, Westerhof, E, Bongers, W, Korsholm, S B, Leipold, F, Oosterbeek, J W, Moseev, D, Stejner, M, and Team, the TEXTOR

Subjects
GYROTRONS, MAGNETIC fields, PLASMA density, SCATTERING (Physics), PLASMA Bernstein waves, TOKAMAKS
Abstract

Anomalous scattering of high power millimetre waves from gyrotrons at 140 and 110 GHz is investigated for plasma with rotating islands at TEXTOR. The magnetic field and plasma density influence the spectral content of the scattered waves and their power levels significantly. Anomalous strong scattering occurs in two density regimes, one at low densities and one at high densities, that also depend on the magnetic field. The two regimes are separated by a quiescent regime without anomalous scattering. Investigations suggest that scattering in the high-density regime is generated at the low-field side intersection of the gyrotron beam and the island position. The transition from the quiescent regime to the high-density regime occurs when the gyrotron frequency is twice the upper hybrid frequency at this position. There is some evidence that the scattering in the low-density regime is generated near the plasma centre. Under this assumption all the observed scattering is generated when the gyrotron frequency is near or below twice the upper hybrid frequency. [ABSTRACT FROM AUTHOR]

Published
2013
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42. Current fast ion collective Thomson scattering diagnostics at TEXTOR and ASDEX Upgrade, and ITER plans (invited).

Author

Korsholm, S. B., Bindslev, H., Meo, F., Leipold, F., Michelsen, P. K., Michelsen, S., Nielsen, S. K., Tsakadze, E. L., Woskov, P., Westerhof, E., FOM ECRH team, Oosterbeek, J. W., Hoekzema, J., Leuterer, F., Wagner, D., and ASDEX Upgrade ECRH team

Subjects
ALPHA rays, PLASMA dynamics, GYROTRONS, MAGNETIC fields, PHYSICS
Abstract

Fast ion physics will play an important role on ITER where confined alpha particles will affect plasma dynamics and overall confinement. Fast ion collective Thomson scattering (CTS) using gyrotrons has the potential to meet the need for measuring the spatially localized velocity distributions of confined fast ions in ITER. Currently, CTS experiments are performed at TEXTOR using a 150 kW, 0.2 s, 110 GHz gyrotron and a receiver upgraded at the Riso\ National Laboratory. The gyrotron and receiver optics have also been upgraded for rapid scanning during a plasma shot. The receiver consists of a nine-mirror quasioptical transmission line including a universal polarizer and a 42-channel data acquisition system, which allows complete coverage of the double sideband scattered spectrum for localized (∼10 cm) time resolved (4 ms) measurements of the ion velocity distribution. At ASDEX Upgrade (AUG) a similar 50-channel CTS receiver has been installed. This CTS system will use the 105 GHz frequency of a dual frequency gyrotron. The gyrotron is presently being commissioned. CTS campaigns are scheduled for the summer of 2006 with a probe power of up to 1 MW for 10 s. This report presents the alignment of the quasioptical transmission line, calibration, and gyrotron tuning of the TEXTOR and AUG CTS systems. We will also review the progress on the design of the proposed fast ion CTS diagnostic for ITER. It is envisaged that scattered radiation from two 60 GHz probe beams launched from the low field side midplane port will be received by two arrays of receivers located on the low and high field sides of the plasma. This geometry will allow the ion velocity distribution near perpendicular and near parallel to the magnetic field to be measured in ten or more spatial locations covering the full plasma cross section. The temporal resolution can be significantly better than the required 100 ms. [ABSTRACT FROM AUTHOR]

Published
2006
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43. Magnetic Island Localization for NTM Control by ECE Viewed Along the Same Optical Path of the ECCD Beam

Author

Bongers, W. A., Goede, A. P. H., Westerhof, E., Oosterbeek, J. W., Doelman, N. J., SchÜller, F. C., de Baar, M. R., Kasparek, W., Wubie, W., Wagner, D., and Stober, J.

Abstract

AbstractNeoclassical tearing modes (NTMs) deteriorate high-pressure tokamak plasma confinement and can be suppressed by electron cyclotron current drive (ECCD). In order to obtain efficient suppression, the ECCD power needs to be deposited at the center of an NTM magnetic island. To enhance efficiency, this power also needs to be synchronized in phase with the rotation of the island. The problem is that of real-time detection and precise localization of the island(s) in order to provide the feedback signal required to control the ECCD power deposition area with an accuracy of 1 to 2 cm. Existing schemes based on mode location, equilibrium reconstruction, and plasma profile measurements are limited in positional and temporal accuracy and moreover will become very complex when applied to ITER. To overcome these limitations, it is proposed to provide the feedback signal from electron cyclotron emission (ECE) measurements taken along the identical line of sight as traced by the incident ECCD millimeter-wave beam but in reverse direction. Experiments on TEXTOR have demonstrated a proof of principle. These measurements motivate the further development and the implementation of such an ECCD-aligned ECE system for NTM control in larger fusion machines. Possible implementation of such a system on ASDEX-Upgrade, based on waveguides equipped with a fast directional switch, is presented in this paper. Possible further development for ITER is also discussed.

Published
2009
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