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49 results on '"Velasco, J.-L."'

1. Robust stellarator optimization via flat mirror magnetic fields

Author

Velasco, J. L., Calvo, I., Sánchez, E., and Parra, F. I.

Subjects
Plasma Physics (physics.plasm-ph), FOS: Physical sciences, Physics - Plasma Physics
Abstract

Stellarator magnetic configurations need to be optimized in order to meet all the required properties of a fusion reactor. In this work, it is shown that a flat-mirror quasi-isodynamic configuration (i.e. a quasi-isodynamic configuration with sufficiently small radial variation of the mirror term) can achieve small radial transport of energy and good confinement of bulk and fast ions even if it is not very close to perfect omnigeneity, and for a wide range of plasma scenarios, including low $\beta$ and small radial electric field. This opens the door to constructing better stellarator reactors. On the one hand, they would be easier to design, as they would be robust against error fields. On the other hand, they would be easier to operate since, both during startup and steady-state operation, they would require less auxiliary power, and the damage to plasma-facing components caused by fast ion losses would be reduced to acceptable levels.

Published
2023
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2. Turbulence prevents core particle depletion in stellarators

Author

Thienpondt, H., García-Regaña, J. M., Calvo, I., Alonso, J. A., Velasco, J. L., González-Jerez, A., Barnes, M., Brunner, K., Ford, O., Fuchert, G., Knauer, J., Pasch, E., Vanó, L., and team, the Wendelstein 7-X

Subjects
Plasma Physics (physics.plasm-ph), FOS: Physical sciences, Physics - Plasma Physics
Abstract

In reactor-relevant plasmas, neoclassical transport drives an outward particle flux in the core of large stellarators and predicts strongly hollow density profiles. However, this theoretical prediction is contradicted by experiments. In particular, in Wendelstein 7-X, the first large optimized stellarator, flat or weakly peaked density profiles are generally measured, indicating that neoclassical theory is not sufficient and that an inward contribution to the particle flux is missing in the core. In this Letter, it is shown that the turbulent contribution to the particle flux can explain the difference between experimental measurements and neoclassical predictions. The results of this Letter also prove that theoretical and numerical tools are approaching the level of maturity needed for the prediction of equilibrium density profiles in stellarator plasmas, which is a fundamental requirement for the design of operation scenarios of present devices and future reactors., Comment: 6 pages, 5 figures, minor changes

Published
2022
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3. Plasma flow measurements based on charge exchange recombination spectroscopy in the Wendelstein 7-X stellarator

Author

Alonso, J. A., Ford, O. P., Vanó, L., Äkäslompolo, S., Buller, S., McDermott, R., Smith, H. M., Baldzuhn, J., Beidler, C. D., Beurskens, M., Bozhenkov, S., Brunner, K. J., Calvo, I., Carralero, D., Dinklage, A., Estrada, T., Fuchert, G., Geiger, J., Knauer, J., Langenberg, A., Pablant, N. A., Pasch, E., Poloskei, P. Zs, Velasco, J. L., Windisch, T., the W7-X Team, Gantenbein, Gerd, Huber, Martina, Illy, Stefan, Jelonnek, John, Kobarg, Thorsten, Lang, Rouven, Leonhardt, Wolfgang, Mellein, Daniel, Papenfuß, Daniel, Thumm, Manfred, Wadle, Simone, Weggen, Jörg, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Technology, Nuclear and High Energy Physics, Condensed Matter Physics, ddc:600
Abstract

The initial operation of neutral beams in Wendelstein 7-X enabled the first measurements of carbon (C6+) temperature and rotation with a multi-chord charge exchange recombination spectroscopy system. In this article we analyse the velocity measurements obtained with this system to infer the profiles of radial electric field, E r, and net parallel velocity of fully stripped carbon ions, V ‖. We include a general treatment of the flow geometry and the velocity corrections due to the energy dependence of the charge exchange cross section. The inverted profiles are compared with neoclassical calculations for various plasma conditions and two magnetic configurations. It is found that both the E r and V ‖ experimental profiles agree in sign and order of magnitude with the neoclassical expectations and reproduce the expected dependencies on plasma parameters and magnetic configuration, within the reduced dataset presented. However, quantitative differences with respect to the neoclassical profiles are observed above the estimated errors in various conditions.

Published
2022
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4. Turbulent impurity transport simulations in Wendelstein 7-X plasmas

Author

García-Regaña, J. M., Barnes, M., Calvo, I., Parra, F. I., Alcusón, J. A., Davies, R., González-Jerez, A., Mollén, A., Sánchez, E., Velasco, J. L., and Zocco, A.

Subjects
Physics, Turbulence, FOS: Physical sciences, Flux, Electron, Plasma, Condensed Matter Physics, 01 natural sciences, Physics - Plasma Physics, Effective nuclear charge, 010305 fluids & plasmas, 3. Good health, Computational physics, Plasma Physics (physics.plasm-ph), Physics::Plasma Physics, Impurity, 0103 physical sciences, Electron temperature, Diffusion (business), 010306 general physics
Abstract

A study of turbulent impurity transport by means of quasilinear and nonlinear gyrokinetic simulations is presented for Wendelstein 7-X (W7-X). The calculations have been carried out with the recently developed gyrokinetic code stella. Different impurity species are considered in the presence of various types of background instabilities: ITG, TEM and ETG modes for the quasilinear part of the work; ITG and TEM for the nonlinear results. While the quasilinear approach allows one to draw qualitative conclusions about the sign or relative importance of the various contributions to the flux, the nonlinear simulations quantitatively determine the size of the turbulent flux and check the extent to which the quasilinear conclusions hold. Although the bulk of the nonlinear simulations are performed at trace impurity concentration, nonlinear simulations are also carried out at realistic effective charge values, in order to know to what degree the conclusions based on the simulations performed for trace impurities can be extrapolated to realistic impurity concentrations. The presented results conclude that the turbulent radial impurity transport in W7-X is mainly dominated by ordinary diffusion, which is close to that measured during the recent W7-X experimental campaigns. It is also confirmed that thermo-diffusion adds a weak inward flux contribution and that, in the absence of impurity temperature and density gradients, ITG- and TEM-driven turbulence push the impurities inwards and outwards, respectively., Comment: 19 pages, 10 figures, 2 tables

Published
2021
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5. A model for the fast evaluation of prompt losses of energetic ions in stellarators

Author

W7-X Team, Velasco, J. L., Calvo, I., Mulas, S., Sánchez, E., Parra, F. I., Cappa, Á., Gantenbein, Gerd, Huber, Martina, Illy, Stefan, Jelonnek, John, Kobarg, Thorsten, Lang, Rouven, Leonhardt, Wolfgang, Mellein, Daniel, Papenfuß, Daniel, Scherer, Theo, Thumm, Manfred, Wadle, Simone, Weggen, Jörg, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Physics, Nuclear and High Energy Physics, Technology, FOS: Physical sciences, Condensed Matter Physics, 01 natural sciences, 7. Clean energy, Physics - Plasma Physics, 010305 fluids & plasmas, Computational physics, Ion, Plasma Physics (physics.plasm-ph), Fast evaluation, Physics::Plasma Physics, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, 010306 general physics, ddc:600
Abstract

A good understanding of the confinement of energetic ions in non-axisymmetric magnetic fields is key for the design of reactors based on the stellarator concept. In this work, we develop a model that, based on the radially-local bounce-averaged drift-kinetic equation, classifies orbits and succeeds in predicting configuration-dependent aspects of the prompt losses of energetic ions in stellarators. Such a model could in turn be employed in the optimization stage of the design of new devices.

Published
2021

6. Impact of magnetic islands on plasma flow and turbulence in W7-X

Author

W7-X Team, Estrada, T., Maragkoudakis, E., Carralero, D., Windisch, T., Velasco, J. L., Killer, C., Andreeva, T., Geiger, J., Dinklage, A., Krämer-Flecken, A., Wurden, G. A., Beurskens, M., Bozhenkov, S., Damm, H., Fuchert, G., Pasch, E., Gantenbein, Gerd, Huber, Martina, Illy, Stefan, Jelonnek, John, Kobarg, Thorsten, Lang, Rouven, Leonhardt, Wolfgang, Mellein, Daniel, Papenfuß, Daniel, Scherer, Theo, Thumm, Manfred, Wadle, Simone, Weggen, Jörg, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Physics, Technology, Nuclear and High Energy Physics, Plasma flow, Turbulence, 0103 physical sciences, Mechanics, ddc:620, 010306 general physics, Condensed Matter Physics, ddc:600, 01 natural sciences, 010305 fluids & plasmas
Abstract

The effect of magnetic islands on plasma flow and turbulence has been experimentally investigated in the stellarator W7-X. Magnetic configurations with the 5/5 magnetic island positioned at the plasma edge, inside the last closed flux surface, are studied. The main diagnostic used in the present work is a V-band Doppler reflectometer that allows the measurement of the perpendicular plasma flow and density fluctuations with good spatial resolution. A characteristic signature of the 5/5 magnetic island is clearly detected in the perpendicular flow profile. The comparison of the experimental flow and the neoclassically driven E × B flow indicates that the island contribution to the flow is maximum at the island boundaries and close to zero at the island O-point. Besides, a reduction in the density fluctuation level is found nearby the island O-point. The similarities between these observations and those found in other devices and in gyrokinetic simulations are discussed.

Published
2021
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7. 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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8. Fast simulations for large aspect ratio stellarators with the neoclassical code KNOSOS

Author

W7-X Team, Velasco, J. L., Calvo, I., Parra, F. I., d’Herbemont, V., Smith, H. M., Carralero, D., Estrada, T., Gantenbein, Gerd, Huber, Martina, Illy, Stefan, Jelonnek, John, Kobarg, Thorsten, Lang, Rouven, Leonhardt, Wolfgang, Mellein, Daniel, Papenfuß, Daniel, Scherer, Theo, Thumm, Manfred, Wadle, Simone, Weggen, Jörg, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Physics, Technology, Nuclear and High Energy Physics, Work (thermodynamics), Tangent, FOS: Physical sciences, Mechanics, Condensed Matter Physics, 01 natural sciences, Physics - Plasma Physics, 010305 fluids & plasmas, law.invention, Plasma Physics (physics.plasm-ph), Large aspect ratio, law, Physics::Plasma Physics, Component (UML), 0103 physical sciences, Code (cryptography), Configuration space, 010306 general physics, ddc:600, Stellarator
Abstract

In this work, a new version of KNOSOS is presented. KNOSOS is a low-collisionality radially-local, bounce-averaged neoclassical code that is extremely fast, and at the same time, includes physical effects often neglected by more standard codes: the component of the magnetic drift that is tangent to the flux-surface and the variation of the electrostatic potential on the flux-surface. An earlier version of the code could only describe configurations that were sufficiently optimized with respect to neoclassical transport. KNOSOS can now be applied to any large aspect ratio stellarator, and its performance is demonstrated by means of detailed simulations in the configuration space of Wendelstein 7-X., Comment: IAEA paper, submitted to Nuclear Fusion

Published
2021
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9. 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

10. Characterization of the radial electric field and edge velocity shear in Wendelstein 7-X

Author

Carralero, D., Estrada, T., Windisch, T., Velasco, J. L., Alonso, J. A., Beurskens, M., Bozhenkov, S., Damm, H., Fuchert, G., Gao, Y., Jakubowski, M., Nieman, H., Pablant, N., Pasch, E., Weir, G., and team, the Wendelstein 7-X

Subjects
Plasma Physics (physics.plasm-ph), FOS: Physical sciences, Physics - Plasma Physics
Abstract

In this work we present the first measurements obtained by the V-band Doppler reflectometer during the second operation phase of Wendelstein 7-X to discuss the influence in the velocity shear layer and the radial electric field, E$_r$, of several plasma parameters such as magnetic configuration, rotational transform or degree of detachment. In the first place, we carry out a systematic characterization of the turbulence rotation velocity profile in order to describe the influence of density and heating power on E$_r$ under the four most frequent magnetic configurations. The $|$E$_r|$ value in the edge is found to increase with configurations featuring higher $\iota$, although this does not apply for the high mirror configuration, KJM. As well, the E$_r$ value in the SOL and the velocity shear near the separatrix are found to display a clear dependence on heating power and density for all configurations. For a number of relevant cases, these results are assessed by comparing them to neoclassical predictions obtained from the codes DKES and KNOSOS, finding generally good agreement with experimental results. Finally, the evolution of E$_r$ at the edge is evaluated throughout the island-divertor detachment regime achieved for the first time in the 2018 campaign. After detachment, $|$E$_r|$ is reduced both at the SOL and edge, and the plasma column shrinks, with the shear layer seemingly moving radially inwards from the separatrix., Comment: Sent for publication to Nuclear Fusion

Published
2020

11. An experimental characterization of core turbulence regimes in Wendelstein 7-X

Author

W7-X Team, Carralero, D., Estrada, T., Maragkoudakis, E., Windisch, T., Alonso, J. A., Beurskens, M., Bozhenkov, S., Calvo, I., Damm, H., Ford, O., Fuchert, G., García-Regaña, J. M., Pablant, N., Sánchez, E., Pasch, E., Velasco, J. L., Gantenbein, Gerd, Huber, Martina, Illy, Stefan, Jelonnek, John, Kobarg, Thorsten, Lang, Rouven, Leonhardt, Wolfgang, Mellein, Daniel, Papenfuß, Daniel, Scherer, Theo, Thumm, Manfred, Wadle, Simone, and Weggen, Jörg

Subjects
Physics, Technology, Nuclear and High Energy Physics, Turbulence, FOS: Physical sciences, Condensed Matter Physics, 01 natural sciences, Physics - Plasma Physics, 010305 fluids & plasmas, law.invention, Characterization (materials science), Computational physics, Plasma Physics (physics.plasm-ph), Core (optical fiber), Physics::Plasma Physics, law, 0103 physical sciences, Wendelstein 7-X, 010306 general physics, ddc:600, Stellarator
Abstract

First results from the optimized helias Wendelstein 7-X stellarator (W7-X) have shown that core transport is no longer mostly neoclassical, as is the case in previous kinds of stellarators. Instead, turbulent transport poses a serious limitation to the global performance of the machine. Several studies have found this particularly relevant for ion transport, with core ion temperatures becoming clamped at relatively low values of $T_{i} \simeq 1.7$ keV, except in the few scenarios in which turbulence can be suppressed. In order to understand turbulent mechanisms at play, it is important to have a clear understanding of the parametric dependencies of turbulent fluctuations, and the relation between them and turbulent transport. In this work we use Doppler reflectometry measurements carried out during a number of relevant operational scenarios to provide a systematic characterization of ion-scale ($k_\perp\rho_i\simeq 1$) density fluctuations in the core of W7-X. Then, we study the relation between fluctuation amplitude and plasma profiles and show how distinct regimes can be defined for the former, depending on normalized gradients $a/L_{ne}$ and $a/L_{Ti}$. Furthermore, we discuss the importance of other potentially relevant parameters such as $T_e/T_i$, $E_r$ or collisionality. Comparing the different regimes, we find that turbulence amplitude depends generally on the gradient ratio $\eta_i=L_{ne}/L_{Ti}$, as would be expected for ITG modes, with the exception of a range of discharges, for which turbulence suppression may be better explained by an ITG to TEM transition triggered by a drop in collisionality. Finally, we show a number of scenarios under which $T_{i,core} > 1.7$ keV is achieved and how core fluctuations are suppressed in all of them, thus providing experimental evidence of microturbulence being the main responsible for the limited ion confinement in W7-X., Comment: Manuscript submitted to Nuclear Fusion in May 2021

Published
2021
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12. Radial electric field and density fluctuations measured by Doppler reflectometry during the post-pellet enhanced confinement phase in W7-X

Author

W7-X Team, Estrada, T., Carralero, D., Windisch, T., Sánchez, E., García-Regaña, J. M., Martínez-Fernández, J., Peña, A. de la, Velasco, J. L., Alonso, J. A., Beurskens, M., Bozhenkov, S., Damm, H., Fuchert, G., Kleiber, R., Pablant, N., Pasch, E., Gantenbein, Gerd, Huber, Martina, Illy, Stefan, Jelonnek, John, Kobarg, Thorsten, Lang, Rouven, Leonhardt, Wolfgang, Mellein, Daniel, Papenfuß, Daniel, Scherer, Theo, Thumm, Manfred, Wadle, Simone, Weggen, Jörg, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Technology, Nuclear and High Energy Physics, Materials science, Plasma turbulence, Magnetic confinement fusion, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, symbols.namesake, Electric field, Phase (matter), 0103 physical sciences, Pellet, symbols, Atomic physics, 010306 general physics, Reflectometry, ddc:600, Doppler effect
Abstract

Radial profiles of density fluctuations and the radial electric field, E r, have been measured using Doppler reflectometry during the post-pellet enhanced confinement phase achieved, under different heating power levels and magnetic configurations, during the 2018 W7-X experimental campaign. A pronounced E r-well is measured with local values as high as −40 kV m−1 in the radial range ρ ∼ 0.7–0.8 during the post-pellet enhanced confinement phase. The maximum E r intensity scales with both the plasma density and electron cyclotron heating power level, following a similar trend to the plasma energy content. A good agreement is found when the experimental E r profiles are compared to simulations carried out using the neoclassical codes, the drift kinetic equation solver (DKES) and kinetic orbit-averaging solver for stellarators (KNOSOS). The density fluctuation level decreases from the plasma edge toward the plasma core and the drop is more pronounced in the post-pellet enhanced confinement phase than in reference gas-fuelled plasmas. Besides, in the post-pellet phase, the density fluctuation level is lower in the high iota magnetic configuration than in the standard one. To determine whether this difference is related to the differences in the plasma profiles or to the stability properties of the two configurations, gyrokinetic simulations have been carried out using the codes stella and EUTERPE. The simulation results point to the plasma profile evolution after the pellet injection and the stabilization effect of the radial electric field profile as the dominant players in the stabilization of the plasma turbulence.

Published
2021
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14. Impact of ECCD on Alfvén eigenmodes in the TJ-II stellarator

Author

Cappa, A., Ascasíbar, E., Castejón, F., García Regaña, J. M., García-Muñoz, M., González-Jerez, A., Lopez-Bruna, D., Liniers, M., Marushchenko, N., Ochando, M., Yamamoto, S., Velasco, J. L., García-Muñoz, M., and García-Muñoz, M. [0000-0002-3241-502X]

Abstract

Trabajo presentado en el 45th EPS Conference on Plasma Physics, celebrada en Praga (República Checa), del 2 al 6 de julio de 2018, The impact of Electron Cyclotron Current Drive (ECCD) on NBI-driven modes has been investigated in the TJ–II low shear stellarator. Experimental results show that a small amount of EC driven current may modify dramatically the spectrum of observed modes (Fig. 1). Applying 240 kW of on-axis ECRH power in counter-ECCD configuration (N|| = +0.2) provokes ∼ 0.5 kA reduction in plasma current. This mild reduction of current is accompanied by a strong change in the behaviour of alfvénic magnetic fluctuations. Changes in rotational transform profile (ι), having a strong influence on the Shear Alfvén Spectrum (SAS) of the device, are the main candidate to explain the observations. The high sensitivity of the SAS structure on ι(ρ) suggests that the interpretation of the results should be made considering all the relevant contributions to the plasma current (NBCD, ECCD and to a lesser extent, the boostrap current boot). For modelling purposes, the STELLGAP and AE3D codes are used to calculate the spectrum and spatial structure of possible gap modes in several shots with different values of the total current. No experimental information on the current profile is available and therefore, the input VMEC magnetic equilibrium, which should be consistent with the plasma current profile, will be obtained using a rough approximation to the unknown NBCD profile and a rigorous theoretical calculation of the ECCD profile (TRAVIS) and the bootstrap current profile.

Published
2018

15. Magnetic configuration effects on the Wendelstein 7-X stellarator

Author

Dinklage A., Beidler C.D., Helander P., Fuchert G., Maassberg H., Rahbarnia K., Sunn Pedersen T., Turkin Y., Wolf R.C., Alonso A., Andreeva T., Blackwell B., Bozhenkov S., Buttenschon B., Czarnecka A., Effenberg F., Feng Y., Geiger J., Hirsch M., Hofel U., Jakubowski M., Klinger T., Knauer J., Kocsis G., Kramer-Flecken A., Kubkowska M., Langenberg A., Laqua H.P., Marushchenko N., Mollen A., Neuner U., Niemann H., Pasch E., Pablant N., Rudischhauser L., Smith H.M., Schmitz O., Stange T., Szepesi T., Weir G., Windisch T., Wurden G.A., Zhang D., Abramovic I., Akaslompolo S., Ali A., Belloso J.A., Aleynikov P., Aleynikova K., Alzbutas R., Anda G., Ascasibar E., Assmann J., Baek S.-G., Baldzuhn J., Banduch M., Barbui T., Barlak M., Baumann K., Behr W., Beidler C., Benndorf A., Bertuch O., Beurskens M., Biedermann C., Biel W., Birus D., Blanco E., Blatzheim M., Bluhm T., Bockenhoff D., Bolgert P., Borchardt M., Borsuk V., Boscary J., Bosch H.-S., Bottger L.-G., Brakel R., Brand H., Brandt C., Brauer T., Braune H., Brezinsek S., Brunner K.-J., Brunner B., Burhenn R., Bussiahn R., Bykov V., Cai Y., Calvo I., Cannas B., Cappa A., Card A., Carls A., Carraro L., Carvalho B., Castejon F., Charl A., Chernyshev F., Cianciosa M., Citarella R., Ciupinski L., Claps G., Cole M.J., Cordella F., Cseh G., Czermak A., Czerski K., Czerwinski M., Czymek G., da Molin A., da Silva A., Dammertz G., de la Pena A., Degenkolbe S., Denner P., Dittmar T., Dhard C.P., Dostal M., Drevlak M., Drewelow P., Drews P., Dudek A., Dundulis G., Durodie F., van Eeten P., 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., Fuhrer M., Funaba T., Galkowski A., Gantenbein G., Gao Y., Regana J.G., 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., Grulke O., Guerard C., Hacker P., Haiduk L., Hammond K., Han X., Harberts F., Harris J.H., Hartfuss H.-J., Hartmann D., Hathiramani D., Hein B., Heinemann B., Heitzenroeder P., Henneberg S., Hennig C., Sanchez J.H., Hidalgo C., Holbe H., Hollfeld K.P., Holting A., Hoschen 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., Kazakov Y., Kenmochi N., Keunecke M., Khilchenko A., Killer C., Kinna D., Kleiber R., Knaup M., Knieps A., Kobarg T., Kochl F., Kolesnichenko Y., Konies A., Koppen M., Koshurinov J., Koslowski R., Konig R., Koster F., Kornejew P., Koziol R., Kramer M., Krampitz R., Kraszewsk P., Krawczyk N., Kremeyer T., Krings T., Krom J., Krychowiak M., Krzesinski G., Ksiazek I., Kuhner G., Kurki-Suonio T., Kwak S., Landreman M., Lang R., Langish S., Laqua H., Laube R., Lazerson S., Lechte C., Lennartz M., Leonhardt W., Lewerentz L., Liang Y., Linsmeier C., Liu S., Lobsien J.-F., Loesser D., Cisquella J.L., Lore J., Lorenz A., Losert M., Lubyako L., Lucke A., Lumsdaine A., Lutsenko V., Maisano-Brown J., Marchuk O., Mardenfeld M., Marek P., Marsen S., Marushchenko M., Masuzaki S., Maurer D., McCarthy K., McNeely P., Meier A., Mellein D., Mendelevitch B., Mertens P., Mikkelsen D., Mishchenko O., Missal B., Mittelstaedt J., Mizuuchi T., Moncada V., Monnich T., Morisaki T., Moseev D., Munk R., Murakami S., Musielok F., Nafradi G., Nagel M., Naujoks D., Neilson H., Neubauer O., Ngo T., Nocentini R., Nuhrenberg C., Nuhrenberg J., Obermayer S., Offermanns G., Ogawa K., Ongena J., Oosterbeek J.W., Orozco G., Otte M., Rodriguez L.P., Pan W., Panadero N., Alvarez N.P., 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., Sitjes A.P., Purps F., Rack M., Recsei S., Reiman A., Reiter D., Remppel F., Renard S., Riedl R., Riemann J., Rimkevicius S., Risse K., Rodatos A., Rohlinger H., Rome M., Rong P., Roscher H.-J., Roth B., 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., Schlisio G., Schluter K.-H., Schmitt J., Schmitz H., Schmuck S., Schneider M., Schneider W., Scholz M., Scholz P., Schrittwieser R., Schroder M., Schroder T., Schroeder R., Schumacher H., Schweer B., Shanahan B., Shikhovtsev I.V., Sibilia M., Sinha P., Siplia 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., Pedersen T.S., Suzuki Y., Svensson J., Szabo V., Szabolics T., Szokefalvi-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., Mora H.T., Tsuchiya H., Tsujimura T., Tulipan S., Turnyanskiy M., Unterberg B., Urban J., Urbonavicius E., Vakulchyk I., Valet S., van Milligen B., Vela L., Velasco J.-L., Vergote M., Vervier M., Vianello N., Viebke H., Vilbrandt R., Vorkorper A., Wadle S., Wang E., Wang N., Warmer F., Wauters T., Wegener L., Weggen J., Wegner T., Wei Y., Wendorf J., Wenzel U., Wiegel B., Wilde F., Winkler E., Winters V., Wolf R., Wolf S., Wolowski J., Wright A., Wurden G., 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., W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society, Science and Technology of Nuclear Fusion, and Turbulence in Fusion Plasmas

Subjects
Physics, Tokamak, Field (physics), General Physics and Astronomy, Plasma, 7. Clean energy, 01 natural sciences, 010305 fluids & plasmas, Bootstrap current, Computational physics, Magnetic field, law.invention, Magnetic mirror, Wendelstein 7-X stellarator, Physics and Astronomy (all), law, Physics::Plasma Physics, 0103 physical sciences, Wendelstein 7-X plasmas, Wendelstein 7-X, 010306 general physics, Stellarator
Abstract

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. As a result, 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. In addition, this type of transport leads to the appearance of a net toroidal plasma current, the so-called bootstrap current. Here, 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. Results from the first experimental campaign of the Wendelstein 7-X stellarator demonstrate that its magnetic-field design grants good control of parasitic plasma currents, leading to long energy confinement times.

Published
2018
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16. 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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17. Oscillatory relaxation of zonal flows in a multi-species stellarator plasma

Author

Sánchez, E., Calvo, I., Velasco, J. L., Medina, F., Alonso, A., Monreal, P., Kleiber, R., team, the TJ-II, and TJ-II Team

Subjects
Physics, Oscillation, Extrapolation, FOS: Physical sciences, Electron, Plasma, Condensed Matter Physics, Kinetic energy, 01 natural sciences, Physics - Plasma Physics, 010305 fluids & plasmas, Computational physics, law.invention, Ion, Plasma Physics (physics.plasm-ph), Nuclear Energy and Engineering, Physics::Plasma Physics, law, 0103 physical sciences, Relaxation (physics), 010306 general physics, Stellarator
Abstract

The low frequency oscillatory relaxation of zonal potential perturbations is studied numerically in the TJ-II stellarator (where it was experimentally detected for the first time). It is studied in full global gyrokinetic simulations of multi-species plasmas. The oscillation frequency obtained is compared with predictions based on single-species simulations using simplified analytical relations. It is shown that the frequency of this oscillation for a multi-species plasma can be accurately obtained from single-species calculations using extrapolation formulas. The damping of the oscillation and the influence of the different inter-species collisions is studied in detail. It is concluded that taking into account multiple kinetic ions and electrons with impurity concentrations realistic for TJ-II plasmas allows to account for the values of frequency and damping rate in zonal flows relaxations observed experimentally., 11 figures, 22 pages

Published
2018
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18. Parallel impurity dynamics in the TJ-II stellarator

Author

Alonso, J A, Velasco, J L, Calvo, I, Estrada, T, Fontdecaba, J M, Garc��a-Rega��a, J M, Geiger, J, Landreman, M, McCarthy, K J, Medina, F, Van Milligen, B Ph, Ochando, M A, Parra, F I, Team, the TJ-II, Team, the W7-X, TJ-II Team, and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

Subjects
Physics, Field line, media_common.quotation_subject, FOS: Physical sciences, Plasma, Condensed Matter Physics, Inertia, 7. Clean energy, 01 natural sciences, Asymmetry, Physics - Plasma Physics, 010305 fluids & plasmas, law.invention, Computational physics, Moment (mathematics), Plasma Physics (physics.plasm-ph), Nuclear Energy and Engineering, law, 0103 physical sciences, Emissivity, 010306 general physics, Stellarator, Beam (structure), media_common
Abstract

We review in a tutorial fashion some of the causes of impurity density variations along field lines and radial impurity transport in the moment approach framework. An explicit and compact form of the parallel inertia force valid for arbitrary toroidal geometry and magnetic coordinates is derived and shown to be non-negligible for typical TJ-II plasma conditions. In the second part of the article, we apply the fluid model including main ion-impurity friction and inertia to observations of asymmetric emissivity patterns in neutral beam heated plasmas of the TJ-II stellarator. The model is able to explain qualitatively several features of the radiation asymmetry, both in stationary and transient conditions, based on the calculated in-surface variations of the impurity density.

Published
2016
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19. Moderation of neoclassical impurity accumulation in high temperature plasmas of helical devices

Author

Velasco, J. L., Calvo, I., Satake, S., Alonso, A., Nunami, M., Yokoyama, M., Sato, M., Estrada, T., Fontdecaba, J. M., Liniers, M., McCarthy, K. J., Medina, F., Van Milligen, B. Ph, Ochando, M., Parra, F., Sugama, H., Zhezhera, A., team, the LHD experimental, and team, the TJ-II

Subjects
Physics, Nuclear and High Energy Physics, neoclassical transport, Magnetic confinement fusion, FOS: Physical sciences, Plasma, Collisionality, Condensed Matter Physics, 7. Clean energy, 01 natural sciences, impurities, Physics - Plasma Physics, 010305 fluids & plasmas, Ion, Plasma Physics (physics.plasm-ph), Large Helical Device, Impurity, Physics::Plasma Physics, Electric field, 0103 physical sciences, Pinch, Atomic physics, stellarators, 010306 general physics
Abstract

Achieving impurity and helium ash control is a crucial issue in the path towards fusion-grade magnetic confinement devices, and this is particularly the case of helical reactors, whose low-collisionality ion-root operation scenarios usually display a negative radial electric field which is expected to cause inwards impurity pinch. In this work we discuss, based on experimental measurements and standard predictions of neoclassical theory, how plasmas of very low ion collisionality, similar to those observed in the impurity hole of the large helical device (Yoshinuma et al and The LHD Experimental Group 2009 Nucl. Fusion 49 062002, Ida et al and The LHD Experimental Group 2009 Phys. Plasmas 16 056111 and Yokoyama et al and LHD Experimental Group 2002 Nucl. Fusion 42 143), can be an exception to this general rule, and how a negative radial electric field can coexist with an outward impurity flux. This interpretation is supported by comparison with documented discharges available in the International Stellarator-Heliotron Profile Database, and it can be extrapolated to show that achievement of high ion temperature in the core of helical devices is not fundamentally incompatible with low core impurity content.

Published
2016
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20. Confirmation of the topology of the Wendelstein 7-X magnetic field to better than 1:100,000

Author

Pedersen T. S., Otte M., Lazerson S., Helander P., Bozhenkov S., Biedermann C., Klinger T., Wolf R. C., Bosch H. -S., Abramovic I., Akaslompolo S., Aleynikov P., Aleynikova K., Ali A., Alonso A., Anda G., Andreeva T., Ascasibar E., Baldzuhn J., Banduch M., Barbui T., Beidler C., Benndorf A., Beurskens M., Biel W., Birus D., Blackwell B., Blanco E., Blatzheim M., Bluhm T., Bockenhoff D., Bolgert P., Borchardt M., Bottger L. -G., Brakel R., Brandt C., Brauer T., Braune H., Burhenn R., Buttenschon B., Bykov V., Calvo I., Cappa A., Carls A., De Carvalho B. B., Castejon F., Cianciosa M., Cole M., Costea S., Cseh G., Czarnecka A., Dal Molin A., De La Cal E., De La Pena A., Degenkolbe S., Dhard C. P., Dinklage A., Dostal M., Drevlak M., Drewelow P., Drews P., Dudek A., Durodie F., Dzikowicka A., Von Eeten P., Effenberg F., Endler M., Erckmann V., Estrada T., Fahrenkamp N., Fellinger J., Feng Y., Figacz W., Ford O., Fornal T., Frerichs H., Fuchert G., Garcia-Munoz M., Geiger B., Geiger J., Gierse N., Gogoleva A., Goncalves B., Gradic D., Grahl M., Gross S., Grote H., Grulke O., Guerard C., Haas M., Harris J., Hartfuss H. -J., Hartmann D., Hathiramani D., Hein B., Heirnich S., Henneberg S., Hennig C., Hernandez J., Hidalgo C., Hidalgo U., Hirsch M., Hofel U., Holbe H., Holting A., Houry M., Huber V., Ionita C., Israeli B., Jablonski S., Jakubowski M., Van Vuuren A. J., Jenzsch H., Kaczmarczyk J., Kallmeyer J. -P., Kamionka U., Kasahara H., Kenmochi N., Kernbichler W., Killer C., Kinna D., Kleiber R., Knauer J., Kochl F., Kocsis G., Kolesnichenko Y., Konies A., Konig R., Kornejew P., Koster F., Kramer-Flecken A., Krampitz R., Krawzyk N., Kremeyer T., Krychowiak M., Ksiazek I., Kubkowska M., Kuhner G., Kurki-Suonio T., Kurz P., Kuttler K., Kwak S., Landreman M., Langenberg A., Lapayese F., Laqua H., Laqua H. -P., Laube R., Laux M., Lentz H., Lewerentz M., Liang Y., Liu S., Lobsien J. -F., Cisquella J. L., Lopez-Bruna D., Lore J., Lorenz A., Lui S., Lutsenko V., Maassberg H., Maisano-Brown J., Marchuk O., Marrelli L., Marsen S., Marushchenko N., Masuzaki S., McCarthy K., McNeely P., Medina F., Milojevic D., Mishchenko A., Missal B., Mittelstaedt J., Mollen A., Moncada V., Monnich T., Moseev D., Nagel M., Naujoks D., Neilson G. H., Neubauer O., Neuner U., Ngo T. -T., Niemann H., Nuhrenberg C., Nuhrenberg J., Ochando M., Ogawa K., Ongena J., Oosterbeek H., Pablant N., Pacella D., Pacios L., Panadero N., Pasch E., Pastor I., Pavone A., Pawelec E., Pedrosa A., Perseo V., Peterson B., Pilopp D., Pisano F., Piulatti M. E., Plunk G., Preynas M., Proll J., Sitjes A. P., Purps F., Rack M., Rahbarnia K., Riemann J., Risse K., Rong P., Rosenberger J., Rudischhauser L., Rummel K., Rummel T., Runov A., Rust N., Ryc L., Saitoh H., Satake S., Schacht J., Schmitz O., Schmuck S., Schneider B., Schneider M., Schneider W., Schrittwieser R., Schroder M., Schroder T., Schroder R., Schumacher H. W., Schweer B., Seki R., Sinha P., Sipilae S., Slaby C., Smith H., Sousa J., Spring A., Standley B., Stange T., Von Stechow A., Stephey L., Stoneking M., Stridde U., Suzuki Y., Svensson J., Szabolics T., Szepesi T., Thomsen H., Travere J. -M., Traverso P., Mora H. T., Tsuchiya H., Tsuijmura T., Turkin Y., Valet S., Van Milligen B., Vela L., Velasco J. -L., Vergote M., Vervier M., Viebke H., Vilbrandt R., Von Thun C. P., Wagner F., Wang E., Wang N., Warmer F., Wauters T., Wegener L., Wegner T., Weir G., Wendorf J., Wenzel U., Werner A., Wie Y., Wiegel B., Wilde F., Windisch T., Winkler M., Winters V., Wright A., Wurden G., Xanthopoulos P., Yamada I., Yasuhara R., Yokoyama M., Zhang D., Zilker M., Zimbal A., Zocco A., Zoletnik S., W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society, Massachusetts Institute of Technology. Department of Physics, Maisano-Brown, Jeannette D., Science and Technology of Nuclear Fusion, Pedersen, T, Otte, M, Lazerson, S, Helander, P, Bozhenkov, S, Biedermann, C, Klinger, T, Wolf, R, Bosch, H, Abramovic, I, Akaslompolo, S, Aleynikov, P, Aleynikova, K, Ali, A, Alonso, A, Anda, G, Andreeva, T, Ascasibar, E, Baldzuhn, J, Banduch, M, Barbui, T, Beidler, C, Benndorf, A, Beurskens, M, Biel, W, Birus, D, Blackwell, B, Blanco, E, Blatzheim, M, Bluhm, T, Bockenhoff, D, Bolgert, P, Borchardt, M, Bottger, L, Brakel, R, Brandt, C, Brauer, T, Braune, H, Burhenn, R, Buttenschon, B, Bykov, V, Calvo, I, Cappa, A, Carls, A, De Carvalho, B, Castejon, F, Cianciosa, M, Cole, M, Costea, S, Cseh, G, Czarnecka, A, Dal Molin, A, De La Cal, E, De La Pena, A, Degenkolbe, S, Dhard, C, Dinklage, A, Dostal, M, Drevlak, M, Drewelow, P, Drews, P, Dudek, A, Durodie, F, Dzikowicka, A, Von Eeten, P, Effenberg, F, Endler, M, Erckmann, V, Estrada, T, Fahrenkamp, N, Fellinger, J, Feng, Y, Figacz, W, Ford, O, Fornal, T, Frerichs, H, Fuchert, G, Garcia-Munoz, M, Geiger, B, Geiger, J, Gierse, N, Gogoleva, A, Goncalves, B, Gradic, D, Grahl, M, Gross, S, Grote, H, Grulke, O, Guerard, C, Haas, M, Harris, J, Hartfuss, H, Hartmann, D, Hathiramani, D, Hein, B, Heirnich, S, Henneberg, S, Hennig, C, Hernandez, J, Hidalgo, C, Hidalgo, U, Hirsch, M, Hofel, U, Holbe, H, Holting, A, Houry, M, Huber, V, Ionita, C, Israeli, B, Jablonski, S, Jakubowski, M, Van Vuuren, A, Jenzsch, H, Kaczmarczyk, J, Kallmeyer, J, Kamionka, U, Kasahara, H, Kenmochi, N, Kernbichler, W, Killer, C, Kinna, D, Kleiber, R, Knauer, J, Kochl, F, Kocsis, G, Kolesnichenko, Y, Konies, A, Konig, R, Kornejew, P, Koster, F, Kramer-Flecken, A, Krampitz, R, Krawzyk, N, Kremeyer, T, Krychowiak, M, Ksiazek, I, Kubkowska, M, Kuhner, G, Kurki-Suonio, T, Kurz, P, Kuttler, K, Kwak, S, Landreman, M, Langenberg, A, Lapayese, F, Laqua, H, Laube, R, Laux, M, Lentz, H, Lewerentz, M, Liang, Y, Liu, S, Lobsien, J, Cisquella, J, Lopez-Bruna, D, Lore, J, Lorenz, A, Lui, S, Lutsenko, V, Maassberg, H, Maisano-Brown, J, Marchuk, O, Marrelli, L, Marsen, S, Marushchenko, N, Masuzaki, S, Mccarthy, K, Mcneely, P, Medina, F, Milojevic, D, Mishchenko, A, Missal, B, Mittelstaedt, J, Mollen, A, Moncada, V, Monnich, T, Moseev, D, Nagel, M, Naujoks, D, Neilson, G, Neubauer, O, Neuner, U, Ngo, T, Niemann, H, Nuhrenberg, C, Nuhrenberg, J, Ochando, M, Ogawa, K, Ongena, J, Oosterbeek, H, Pablant, N, Pacella, D, Pacios, L, Panadero, N, Pasch, E, Pastor, I, Pavone, A, Pawelec, E, Pedrosa, A, Perseo, V, Peterson, B, Pilopp, D, Pisano, F, Piulatti, M, Plunk, G, Preynas, M, Proll, J, Sitjes, A, Purps, F, Rack, M, Rahbarnia, K, Riemann, J, Risse, K, Rong, P, Rosenberger, J, Rudischhauser, L, Rummel, K, Rummel, T, Runov, A, Rust, N, Ryc, L, Saitoh, H, Satake, S, Schacht, J, Schmitz, O, Schmuck, S, Schneider, B, Schneider, M, Schneider, W, Schrittwieser, R, Schroder, M, Schroder, T, Schroder, R, Schumacher, H, Schweer, B, Seki, R, Sinha, P, Sipilae, S, Slaby, C, Smith, H, Sousa, J, Spring, A, Standley, B, Stange, T, Von Stechow, A, Stephey, L, Stoneking, M, Stridde, U, Suzuki, Y, Svensson, J, Szabolics, T, Szepesi, T, Thomsen, H, Travere, J, Traverso, P, Mora, H, Tsuchiya, H, Tsuijmura, T, Turkin, Y, Valet, S, Van Milligen, B, Vela, L, Velasco, J, Vergote, M, Vervier, M, Viebke, H, Vilbrandt, R, Von Thun, C, Wagner, F, Wang, E, Wang, N, Warmer, F, Wauters, T, Wegener, L, Wegner, T, Weir, G, Wendorf, J, Wenzel, U, Werner, A, Wie, Y, Wiegel, B, Wilde, F, Windisch, T, Winkler, M, Winters, V, Wright, A, Wurden, G, Xanthopoulos, P, Yamada, I, Yasuhara, R, Yokoyama, M, Zhang, D, Zilker, M, Zimbal, A, Zocco, A, Zoletnik, S, Universidad de Sevilla. Departamento de Física Atómica, Molecular y Nuclear, Department of Applied Physics, Aalto-yliopisto, Aalto University, and Pacella, D.

Subjects
Tokamak, Plasma parameters, Science, General Physics and Astronomy, Topology (electrical circuits), Topology, 7. Clean energy, 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, 010305 fluids & plasmas, law.invention, law, 0103 physical sciences, 010306 general physics, Physics, Fusion, Wendelstein7-X, Stellarator, Multidisciplinary, ta114, General Chemistry, Plasma, Fusion power, Magnetic field, Erratum, Wendelstein 7-X, Stellarator
Abstract

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, Wendelstein 7-X (W7-X), has just started operation, 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. Here we show the first physics results, 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., Early stellarator designs suffered from high particle losses, an issue that can be addressed by optimization of the coils. Here the authors measure the magnetic field lines in the Wendelstein 7-X stellarator, confirming that the complicated design of the superconducting coils has been realized successfully.

Published
2016

21. Electrostatic potential variation on the flux surface and its impact on impurity transport

Author

Garc��a-Rega��a, J. M., Beidler, C. D., Turkin, Y., Kleiber, R., Helander, P., Maa��berg, H., Alonso, J. A., and Velasco, J. L.

Subjects
Plasma Physics (physics.plasm-ph), FOS: Physical sciences, Physics - Plasma Physics
Abstract

The particle transport of impurities in magnetically confined plasmas under some conditions does not find, neither quantitatively nor qualitatively, a satisfactory theory-based explanation. This compromise the successful realization of thermo-nuclear fusion for energy production since its accumulation is known to be one of the causes that leads to the plasma breakdown. In standard reactor-relevant conditions this accumulation is in most stellarators intrinsic to the lack of toroidal symmetry, that leads to the neoclassical electric field to point radially inwards. This statement, that the standard theory allows to formulate, has been contradicted by some experiments that showed weaker or no accumulation under such conditions \cite{Ida_pop_16_056111_2009, Yoshinuma_nf_49_062002_2009}. The charge state of the impurities makes its transport more sensitive to the electric fields. Thus, the short length scale turbulent electrostatic potential or its long wave-length variation on the flux surface $\Phi_{1}$ -- that the standard neoclassical approach usually neglects -- might possibly shed some light on the experimental findings. In the present work the focus is put on the second of the two, and investigate its influence of the radial transport of C$^{6+}$. We show that in LHD it is strongly modified by $\Phi_{1}$, both resulting in mitigated/enhanced accumulation at internal/external radial positions; for Wendelstein 7-X, on the contrary, $\Phi_{1}$ is expected to be considerably smaller and the transport of C$^{6+}$ not affected up to an appreciable extent; and in TJ-II the potential shows a moderate impact despite of the large amplitude of $\Phi_1$ for the parameters considered.

Published
2015

23. Damping of radial electric field fluctuations in the TJ-II stellarator

Author

Velasco, J L, Alonso, J A, Calvo, I, Arévalo, J, Sánchez, E, Eliseev, L, Perfilov, S, Estrada, T, López-Fraguas, A, Hidalgo, C, and team, the TJ-II

Subjects
Physics, Range (particle radiation), FOS: Physical sciences, Plasma, Electron, Mechanics, Condensed Matter Physics, Physics - Plasma Physics, law.invention, Ion, Plasma Physics (physics.plasm-ph), Shear (sheet metal), Nuclear Energy and Engineering, law, Physics::Plasma Physics, Electric field, Physics::Space Physics, Relaxation (physics), Stellarator
Abstract

The drift-kinetic equation is solved for low density TJ-II plasmas employing slowly varying, time-dependent profiles. This allows to simulate density ramp-up experiments and to describe from first principles the formation and physics of the radial electric field shear, which is associated to the transition from electron to ion root. We show that the range of frequencies of plasma potential fluctuations in which zonal flows are experimentally observed is neoclassically undamped in a neighbourhood of the transition. This makes the electron root regime of stellarators, close to the transition to ion root, a propitious regime for the study of zonal-flow evolution. We present simulations of collisionless relaxation of zonal flows, in the sense of the Rosenbluth and Hinton test, that show an oscillatory behaviour in qualitative agreement with the experiment close to the transition.

Published
2013

24. Efecto de la fuente de ácidos grasos sobre la respuesta productiva, características de la canal, concentración de urea en plasma y perfil de ácidos grasos en carne de cerdos alimentados con dietas estándar o con baja proteína

Author

Martínez-Aispuro, M., Figueroa-Velasco, J. L., Zamora-Zamora, V., Sánchez-Torres, M. T., Ortega-Cerrilla, M. E., Cordero-Mora, J. L., Ruiz-Flores, A., and González-Muñoz, S. S.

Subjects
feed additives, feeding management, manejo alimenticio, Livestock, Animal Production, Swine Nutrition, aditivos alimenticios, calidad de carne de cerdo, food and beverages, pork meat quality, ganadería, producción animal
Abstract

Thirty six Landrace × Yorkshire barrows with 18.6 kg of initial body weight were used to evaluate three sources of fatty acids: crude soybean oil, conjugated linoleic acid (CLA), and soybean soapstock in standard crude protein (CP) and low-protein diets for starter (21 d; 205, 160 g kg-1 CP), growing (28 d; 160, 145 g kg-1 CP), and finishing (29 d; 140, 125 g kg-1 CP) phases. Growth performance, carcass characteristics, plasma urea nitrogen concentration and fatty acid profile in meat were evaluated. The reduction of CP diminished average daily gain, feed:gain ratio, longissimus muscle area and plasma urea nitrogen concentration in nursery pigs; reduced longissimus muscle area and plasma urea nitrogen concentration in growing pigs; increased average daily feed intake, and reduced lean meat percentage and plasma urea nitrogen content in finishing pigs. It also increased c9, t11 and c11, t9 CLA isomers and total lipids and lowered eicosapentaenoic and docosahexaenoic acids concentrations in semimembranosus muscle; linolenic acid decreased with low-protein diets in longissimus and semimembranosus muscles; the oil type affected the concentration of c9, t11 and c11, t9 CLA isomers and total saturated fatty acids in semimembranosus muscle; CLA increased individually and total saturated fatty acids, reduced linoleic and docosapentaenoic acids, and increased total lipids in longissimus muscle. These results indicate that decreasing CP changes the profile of fatty acids. The soybean soapstock can replace crude soybean oil in pig diets; while conjugated linoleic acid does not improve response of pigs fed standard- or low-protein diets., Se utilizaron 36 cerdos machos castrados (18,6 ± 2,3 kg peso inicial) para evaluar tres fuentes de ácidos grasos: aceite crudo de soya, ácido linoleico conjugado (ALC) y aceite de soya acidulado en dietas estándar en proteína bruta (PB) y con baja proteína para iniciación (21 d; 205, 160 g kg-1 PC), crecimiento (28 d; 160, 145 g kg-1 PC), y finalización (29 d; 140, 125 g kg-1 PC). Se evaluó la respuesta productiva, características de la canal, urea en plasma y perfil de ácidos grasos en carne. La reducción de PB disminuyó la ganancia de peso, conversión alimenticia, área del músculo longissimus y urea en plasma en iniciación; redujo el área del músculo longissimus y urea en plasma durante el crecimiento; aumentó el consumo, disminuyó el porcentaje de carne magra y la urea en plasma en finalización. También aumentó los isómeros c9, t11 y c11, t9 del ALC y lípidos totales, redujo los ácidos eicosapentaenoico y docosahexaenoico en músculo semimembranosus y disminuyó el ácido linolénico en ambos músculos. El tipo de aceite afectó a la concentración de isómeros c9, t11 y c11, t9 del ALC y total de ácidos grasos saturados en músculo semimembranosus; el ALC aumentó los ácidos grasos individualmente y total de saturados, redujo el linoleico y docosapentaenoico; aumentó el total de lípidos en músculo longissimus. Esto indica que reducir PB cambia el perfil de ácidos grasos, que el aceite de soya acidulado puede reemplazar al aceite crudo de soya en dietas para cerdos y que el ALC no mejora la respuesta de cerdos alimentados con dietas estándar o con baja proteína.

Published
2012

25. Monte Carlo simulations for statistical physics: Janus

Author

Belletti, F., Cotallo, M., Cruz, A., Fernandez, L. A., Gordillo Guerrero, A., Guidetti, M., Maiorano, Andrea, Mantovani, F., Marinari, Vincenzo, Martin Mayor, V., Munoz Sudupe, A., Navarro, D., Parisi, Giorgio, Perez Gaviro, S., Rossi, M., Ruiz Lorenzo, J. J., Saenz Lorenzo, J. F., Schifano, S. F., Sciretti, D., Tarancon, A., Tripiccione, R., Velasco, J. L., Yllanes, D., and Zanier, G.

Published
2009

26. IANUS: Scientific Computing on an FPGA-based Architecture

Author

Belletti, F., Cotallo, M., Cruz, A., Fernández, L. A., Gordillo, A., Maiorano, A., Filippo Mantovani, Marinari, E., Martín-Mayor, V., Muñoz-Sudupe, A., Navarro, D., Pérez-Gaviro, S., Rossi, M., Ruiz-Lorenzo, J. J., Schifano, S. F., Sciretti, D., Tarancón, A., Tripiccione, R., and Velasco, J. L.

Subjects
SPECIAL-PURPOSE COMPUTER, SIMULATIONS, NO
Published
2008

27. Monte Carlo simulations for statistical physics: Janus

Author

Belletti, Francesco, Cotallo, M., Cruz, A., Fernandez, L. A., Gordillo Guerrero, A., Guidetti, Marco, Maiorano, A., Mantovani, Filippo, Marinari, E., Martin Mayor, V., Muñoz Sudupe, A., Navarro, D., Parisi, G., Perez Gaviro, S., Rossi, M., Ruiz Lorenzo, J. J., Saenz Lorenzo, J. F., Schifano, Sebastiano Fabio, Sciretti, D., Tarancon, A., Tripiccione, Raffaele, Velasco, J. L., Yllanes, D., Zanier, G., and The JANUS Collaboration

Subjects
FPGA-based architecture, Spin Glass Monte Carlo Simulations
Published
2008

28. Nonequilibrium spin glass dynamics from picoseconds to 0.1 seconds

Author

Belletti, F., Cotallo, M., Cruz, A., Fernandez, L. A., Gordillo-Guerrero, A., Guidetti, M., Maiorano, A., Mantovani, F., Marinari, E., Martin-Mayor, V., Sudupe, A. Munoz, Navarro, D., Parisi, G., Perez-Gaviro, S., Ruiz-Lorenzo, J. J., Schifano, S. F., Sciretti, D., Tarancon, A., Tripiccione, R., Velasco, J. L., and Yllanes, D.

Subjects
FOS: Physical sciences, Disordered Systems and Neural Networks (cond-mat.dis-nn), Condensed Matter - Disordered Systems and Neural Networks, Computational Physics (physics.comp-ph), Physics - Computational Physics
Abstract

We study numerically the nonequilibrium dynamics of the Ising Spin Glass, for a time that spans eleven orders of magnitude, thus approaching the experimentally relevant scale (i.e. {\em seconds}). We introduce novel analysis techniques that allow to compute the coherence length in a model-independent way. Besides, we present strong evidence for a replicon correlator and for overlap equivalence. The emerging picture is compatible with non-coarsening behavior., Comment: 4 pages, 4 eps color figures. Version accepted for publication in Phys. Rev. Lett

Published
2008
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29. IANUS: Scientific Computing on an FPGA-Based Architecture

Author

Belletti, F., Cotallo, M., Cruz, A., Fernandez, L. A., Gordillo, A., Maiorano, A., Mantovani, F., Marinari, V., Martin Mayor, V., Munoz Sudupe, A., Navarro, D., Perez Gaviro, S., Rossi, M., Ruiz Lorenzo, J. J., Schifano, S. F., Sciretti, D., Tarancon, A., Tripiccione, R., and Velasco, J. L.

Subjects
Computer Science (all)
Published
2008

30. IANUS: an FPGA-based System for High Performance Scientific Computing

Author

Belletti, F., Cotallo, M., Cruz, A., Fernandez, L. A., Gordillo, A., Maiorano, Andrea, Mantovani, F., Marinari, Vincenzo, MARTIN MAYOR, V., MUNOZ SUDUPE, A., Navarro, D., PEREZ GAVIRO, S., Rossi, M., RUIZ LORENZO, J. J., Schifano, S. F., Sciretti, D., Tarancon, A., Tripiccione, R., and Velasco, J. L.

Published
2007

31. Rotíferos de la Comunidad de Madrid

Author

Velasco, J. L.

Subjects
Madrid, Spain, Rotifers, Rotíferos, España
Abstract

The 135 taxa of Rotifers (Rotatoria) reported so far from Comunidad de Madrid, represented almost one third (30,6%) of the 441 taxa reported for Spain as a whole. In this paper we present the precise localities and collection data for species located in Madrid. Of all localities sampled, the Laguna de San Juan appears as particularly interesting, since first reports for Spain of six species have been made from this small lake located on gypsum soils. En la Comunidad de Madrid han sido citados hasta la fecha 135 taxa de Rotíferos (Rotifera) que representan, aproximadamente, un tercio (30,6%) de los 441 taxa descritos en España. En este trabajo se presentan las localidades precisas y los datos de colecta de las especies de Madrid. De las localidades muestreadas destaca por su interés la Laguna de San Juan. De esta laguna, localizada en terrenos yesíferos, se aportan las primeras citas para España de seis species.

Published
2006
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32. Ianus: an Adpative FPGA Computer

Author

Ianus Collaboration, Belletti, F., Campos, I., Cruz, A., Fernandez, L. A., Jimenez, S., Maiorano, A., Mantovani, F., Marinari, E., Martin-Mayor, V., Navarro, D., Munoz-Sudupe, A., Gaviro, S. Perez, Poli, G., Ruiz-Lorenzo, J. J., Schifano, F., Sciretti, D., Tarancon, A., Tellez, P., Tripiccione, R., and Velasco, J. L.

Subjects
Condensed Matter - Other Condensed Matter, FOS: Physical sciences, Disordered Systems and Neural Networks (cond-mat.dis-nn), Computational Physics (physics.comp-ph), Condensed Matter - Disordered Systems and Neural Networks, Physics - Computational Physics, Other Condensed Matter (cond-mat.other)
Abstract

Dedicated machines designed for specific computational algorithms can outperform conventional computers by several orders of magnitude. In this note we describe {\it Ianus}, a new generation FPGA based machine and its basic features: hardware integration and wide reprogrammability. Our goal is to build a machine that can fully exploit the performance potential of new generation FPGA devices. We also plan a software platform which simplifies its programming, in order to extend its intended range of application to a wide class of interesting and computationally demanding problems. The decision to develop a dedicated processor is a complex one, involving careful assessment of its performance lead, during its expected lifetime, over traditional computers, taking into account their performance increase, as predicted by Moore's law. We discuss this point in detail.

Published
2005

33. Flow cytometric analysis of mast cells from normal and pathological human bone marrow samples: identification and enumeration

Author

Orfao, A., Escribano, L., Jesús Villarrubia, Velasco, J. L., Cerveró, C., Ciudad, J., Navarro, J. L., and San Miguel, J. F.

Subjects
Bone Marrow, Humans, Bone Marrow Cells, Cell Count, Cell Separation, Mast Cells, Flow Cytometry, Leukemia, Lymphocytic, Chronic, B-Cell, Research Article
Abstract

In the present paper we have used a three-color immunofluorescence procedure combined with flow cytometry cell analysis and sorting for the identification and enumeration of human mast cells in both normal and pathological bone marrow samples. Our results show that bone marrow mast cells are clearly identifiable on the basis of their light-scatter properties and strong CD117 expression. These cells were negative for the CD34, CD38, and BB4 antigens. In addition, they were CD33+ and displayed a high reactivity for the anti-IgE monoclonal antibody. The identity of the CD117-strong+ cells (mast cells) was confirmed by both microscopic examination and flow cytometry analysis. The overall frequency of mast cells in the bone marrow samples analyzed in the present study was constantly lower than 1%. The lowest frequencies corresponded to normal human bone marrow samples (0.0080 +/- 0.0082%) and the highest to those patients suffering from indolent systemic mast cell disease (0.40 +/- 0.13%). In summary, our results show that the identification and enumeration of bone marrow mast cells can be achieved using multiparametric flow cytometry. Moreover, once identified, mast cells are suitable for being characterized from the phenotypic and the functional point of view, facilitating the comparison between normal and abnormal mast cells.

Published
1996

35. Core confinement in wendelstein 7-X limiter plasmas

Author

Dinklage, A., Alonso, A., Baldzuhn, J., Beidler, C. D., Biedermann, C., Blackwell, B., Bozhenkov, S., Brakel, R., Buttenschön, B., Feng, Y., Fuchert, G., Geiger, J., Helander, P., Hirsch, M., Hoefel, U., Knauer, J., Krämer-Flecken, A., Landreman, M., Langenberg, A., Laqua, H. P., Maaßberg, H., Pablant, N. A., Pasch, E., Rahbarnia, K., Rudischhauser, L., Smith, H., Stange, T., Stephey, L., Trimino-Mora, H., Turkin, Yu, Velasco, J. -L, Glen Wurden, Zhang, D., Andreeva, T., Beurskens, M., Blanco, E., Bosch, H. -S, Burhenn, R., Cappa, A., Czarnecka, A., Dostal, M., Drews, P., Endler, M., Estrada, T., Fornal, T., Grulke, O., Hartmann, D., Harris, J. H., Jakubowski, M., Klinger, T., Klose, S., Kocsis, G., König, R., Kornejew, P., Krawczyk, N., Krychowiak, M., Kubkowska, M., Ksiazek, I., Lazerson, S., Liang, Y., Liu, S., Marchuk, O., Marsen, S., Marushchenko, N., Moncada, V., Moseev, D., Naujoks, D., Niemann, H., Otte, M., Pedersen, T. S., Pisano, F., Riße, K., Rummel, T., Schmitz, O., Satake, S., Schröder, T., Szepesi, T., Thomsen, H., Traverso, P., Tsuchiya, H., Valson, P., Wang, N., Wauters, T., Weir, G., Wolf, R., Yokoyama, M., and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

36. MAIN RESULTS OF THE FIRST EXPERIMENTAL CAMPAIGN IN THE STELLARATOR W7-X

Author

Marushchenko, N. B., Dinklage, A., Alonso, A., Baldzuhn, J., Beidler, C. D., Biedermann, C., Blackwell, B., Sergey Bozhenkov, Brakel, R., Buttenschön, B., Feng, Y., Fuchert, G., Geiger, J., Hirsch, M., Hoefel, U., Knauer, J., Krämer-Flecken, A., Langenberg, A., Laqua, H. P., Landreman, M., Maassberg, H., Pablant, N. A., Pasch, E., Rahbarnia, K., Rudischhauser, L., Stange, T., Stephey, L., Trimino-Mora, H., Turkin, Y., Velasco, J. -L, Wurden, G., Zhang, D., Andreeva, T., Beurskens, M., Blanco, E., Bosch, H. -S, Burhenn, R., Cappa, A., Czarnecka, A., Dostal, M., Drews, P., Endler, M., Estrada, T., Fornal, T., Grulke, O., Hartmann, D., Harris, J. H., Helander, P., Jakubowski, M., Klinger, T., Klose, S., Kocsis, G., König, R., Kornejew, P., Krawczyk, N., Krychowiak, M., Kubkowska, M., Kiazek, I., Lazerson, S., Liang, Y., Liu, S., Marchuk, O., Marsen, S., Moncada, V., Moseev, D., Naujoks, D., Niemann, H., Otte, M., Pedersen, T. S., Pisano, F., Riße, K., Rummel, T., Schmitz, O., Satake, S., Smith, H., Schröder, T., Szepesi, T., Thomsen, H., Traverso, P., Tsuchiya, M., Wang, N., Wauters, T., Weir, G., Wolf, R., and Yokoyama, M.

Subjects
Magnetic confinement
Abstract

A summary of the first operational phase (OP1.1) at the stellarator W7-X is given. The operational setup of heating and diagnostics as well the results of experiments are briefly described. Plasma parameters and confinement are better than expected: T(b)> 8 keV and T(i)> 2 keV at n(b)≈ 3×10¹⁹ m⁻³ yielding β0 ≈ 2.5 %. The results for ECR heating with X2-mode as well the ECCD are in good agreement with the theory predictions. The heating scenario with the O2-mode alone was successfully first time performed. Stellarator specific regime of core “electron root” confinement was obtained. Представлены итоги первой экспериментальной кампании (ОР1.1) на стеллараторе W7-X. Вкратце описана специфика эксперимента, методов нагрева и основных диагностик. Параметры плазмы и удержание, полученные в экспериментах, превысили ожидаемые: T(b)> 8 кэВ и T(i)> 2 кэВ при ≈ n(b)≈ 3×10¹⁹ m⁻³, что соответствует β0 ≈ 2.5 %. Результаты по ЭЦР-нагреву на Х2-моде, а также по токам увлечения согласуются с теорией. Впервые был успешно реализован сценарий нагрева на О2-моде. Был также получен специфический для стеллараторов режим "электронного корня" удержания. Представлені підсумки першої експериментальної кампанії (ОР1.1) на стелараторі W7-X. Коротко описана специфіка експерименту, методів нагріву та діагностики. Параметри плазми та удержання, отримані в експериментах, перевищили очікувані: T(b)> 8 кеВ та T(i)> 2 > 2 кеВ при ≈ n(b)≈ 3×10¹⁹ m⁻³, що відповідає β0 ≈ 2.5 %. Результати по ЕЦР-нагріву на Х2-моді, а також по струмам захоплення відповідають теорії. Вперше був успішно реалізований сценарій нагріву на О2-моді. Був також успішно реалізований специфічний для стелараторів режим "електронного кореня" утримання.

37. Investigation of the core radial electric field in Wendelstein 7-X plasmas

Author

Pablant, N. A., Dinklage, A., Landreman, M., Langenberg, A., Alonso, A., Beidler, C. D., Beurskens, M., Bitter, M., Bozhenkov, S., Burhenn, R., Delgado-Aparicio, L. F., Fuchert, G., Gates, D. A., Geiger, J., Hill, K. W., Hoefel, U., Hirsch, M., Knauer, J., Krämer-Flecken, A., Lazerson, S., Maassberg, H., Marchuk, O., Marushchenko, N. B., Mikkelsen, D. R., Pasch, E., Satake, S., Smith, H., Svensson, J., Traverso, P., Turkin, Y., Valson, P., Velasco, J. L., Gavin Weir, Windisch, T., Wolf, R. C., Yokoyama, M., Zhang, D., and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

39. Impact of ECCD on Alfvén eigenmodes in the TJ-II stellarator

Author

Cappa, Á, López-Bruna, D., Velasco, J. L., González-Jerez, A., García Regaña, J. M., Ochando, M., Yamamoto, S., Liniers, M., Ascasíbar, E., Castejón, F., Fontdecaba, J. M., Medina, F., García Muñoz, M., and Marushchenko, N.

40. ZIVIS: A City Computing Platform Based on Volunteer Computing

Author

Antoli, B., Castejon, F., Giner, A., Losilla, G., Reynolds, J. M., Rivero, A., Sangiao, S., Serrano, F., Alfonso Tarancon, Valles, R., Velasco, J. L., Tobio, Jg, Biempica, Rd, Cabido, Il, Santamaria, Mjm, Dominguez, Jt, and Tato, Ag

41. Dependence of the core radial electric field on ion and electron temperature in W7-X

Author

Pablant, N. A., Langenberg, A., Alonso, A., Baldzuhn, J., Beidler, C. D., Bitter, M., Bozhenkov, S., Brunner, K. J., Burhenn, R., Dinklage, A., Fuchert, G., Gates, D. A., Geiger, J., Hill, K. W., Hirsch, M., Hoefel, U., Kazakov, Y., Knauer, J., Laqua, H., Landreman, M., Lazerson, S., Maassberg, H., Marchuk, O., Pasch, E., Pavone, A., Satake, S., Schroeder, T., Svensson, J., Traverso, P., Turkin, Y., Velasco, J. L., Stechow, A., Felix Warmer, Weir, G., Wolf, R. C., Zhang, D., and W7-X Team, Max Planck Institute for Plasma Physics, Max Planck Society

42. MAIN RESULTS OF THE FIRST EXPERIMENTAL CAMPAIGN IN THE STELLARATOR W7-X

Author

Marushchenko, N. B., Dinklage, A., Alonso, A., Baldzuhn, J., Beidler, C. D., Biedermann, C., Blackwell, B., Bozhenkov, S., Brakel, R., Buttenschoen, B., Feng, Y., Fuchert, G., Geiger, J., Hirsch, M., Hoefel, U., Knauer, J., Kraemer-Flecken, A., Langenberg, A., Laqua, H. P., Landreman, M., Maassberg, H., Novimir Pablant, Pasch, E., Rahbarnia, K., Rudischhauser, L., Stange, T., Stephey, L., Trimino-Mora, H., Turkin, Yu, Velasco, J. -L, Wurden, G., Zhang, D., Andreeva, T., Beurskens, M., Blanco, E., Bosch, H. -S, Burhenn, R., Cappa, A., Czarnecka, A., Dostal, M., Drews, P., Endler, M., Estrada, T., Fornal, T., Grulke, O., Hartmann, D., Harris, J. H., Helander, P., Jakubowski, M., Klinger, T., Klose, S., Kocsis, G., Koenig, R., Kornejew, P., Krawczyk, N., Krychowiak, M., Kubkowska, M., Kiazek, Z., Lazerson, S., Liang, Y., Liu, S., Marchuk, O., Marsen, S., Moncada, V., Moseev, D., Naujoks, D., Niemann, H., Otte, M., Pedersen, T. S., Pisano, F., Risse, K., Rummel, T., Schmitz, O., Satake, S., Smith, H., Schroeder, T., Szepesi, T., Thomsen, H., Traverso, P., Tsuchiya, M., Wang, N., Wauters, T., Weir, G., Wolf, R., Yokoyama, M., and X Team, W.

45. Grid Computing for Fusion Research

Author

Castejon, F., Gomez-Iglesias, A., Bustos, A., Campos, I., Cappa, C. E., Cardenas-Montes, M., Fernandez, L. A., Flores, L. A., Guasp, J., Huedo, E., Lopez-Bruna, D., Llorente, I. M., Victor Martin-Mayor, Mayo, R., Montero, R. S., Montes, E., Reynolds, J. M., Rodriguez, M., Rubio-Montero, A. J., Tarancon, A., Tereshchenko, M., Vazquez-Poletti, J. L., Velasco, J. L., Garcia, Vh, Barreira, G., Espert, Ib, and Gomes, J.

46. The interactive European grid: Project objectives and achievements

Author

Marco, J., Campos, I., Coterillo, I., Díaz, I., López, A., Marco, R., Martínez-Rivero, C., Orviz, P., Rodríguez, D., Gomes, J., Borges, G., Montecelo, M., David, M., Silva, B., Dias, N., João Martins, Fernández, C., García-Tarrés, L., Veiga, C., Cordero, D., Cacheiro, J. L., López, I., García-Tobío, J., Costas, N., Mouriño, J. C., Gómez, A., Bogacki, W., Meyer, N., Owsiak, M., Płóciennik, M., Pospieszny, M., Zawadzki, M., Hammad, A., Hardt, M., Fernández, E., Heymann, E., Senar, M. A., Padee, A., Nawrocki, K., Wislicki, W., Heinzlreiter, P., Baumgartner, M., Rosmanith, H., Kranzmüller, D., Volkert, J., Kenny, S., Coghlan, B., Pajak, R., Mosurska, Z., Szymocha, T., Lason, P., Skital, L., Funika, W., Korcyl, K., Pieczykolan, J., Bałos, K., Słota, R., Guzy, K., Dutka, L., Kitowski, J., Zieliński, K., Hluchý, L., Dobrucký, M., Šimo, B., Habala, O., Astalos, J., Ciglan, M., Sípková, V., Babík, M., Gatial, E., Vallés, R., Reynolds, J. M., Serrano, F., Tarancón, A., Velasco, J. L., Castejón, F., Dichev, K., Keller, R., and Stork, S.

49. Molecular structure determination: a testing ground for high-level quantum-chemical computations

Author

PUZZARINI, CRISTINA, C. Puzzarini, and A. REYES VELASCO, J. L. SANZ VICARIO

Subjects
Physics::Chemical Physics
Abstract

An complete overview on various methodologies for determining molecular structure by means of quantum-chemistry as well as on the accuracy nowadays reachable will be presented. Taking the coupled-cluster singles and doubles (CCSD) level augmented by a perturbative treatment of triple excitations (CCSD(T)) as starting point, emphasis will be given to extrapolation techniques as well as to inclusion of “minor” contributions, such as core-correlation effects, higher-excitation and relativistic effects. The combination of experimental ground-state rotational constants with calculated vibrational corrections to determine reliable equilibrium geometries for polyatomic molecules will be also considered. Due to the computational contribution, these structures are usually referred to as ''empirical'', ''mixed experimental/theoretical'', or ''semi-experimental''. The comparison to pure ab initio structural determinations will be also discussed. Illustrative examples, mostly for small to medium-sized molecules, will be presented.

Published
2010

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