Browsing by Author "Ford, O."

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  • 4D and 5D phase-space tomography using slowing-down physics regularization
    (2023-07) Schmidt, B. S.; Salewski, M.; Moseev, D.; Baquero-Ruiz, M.; Hansen, P. C.; Eriksson, J.; Ford, O.; Gorini, G.; Järleblad, H.; Kazakov, Ye O.; Kulla, D.; Lazerson, S.; Mencke, J. E.; Mykytchuk, D.; Nocente, M.; Poloskei, P.; Rud, M.; Snicker, A.; Stagner, L.; Äkäslompolo, S.; , W7-X Team
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We compute reconstructions of 4D and 5D fast-ion phase-space distribution functions in fusion plasmas from synthetic projections of these functions. The fast-ion phase-space distribution functions originating from neutral beam injection (NBI) at TCV and Wendelstein 7-X (W7-X) at full, half, and one-third injection energies can be distinguished and particle densities of each component inferred based on 20 synthetic spectra of projected velocities at TCV and 680 at W7-X. Further, we demonstrate that an expansion into a basis of slowing-down distribution functions is equivalent to regularization using slowing-down physics as prior information. Using this technique in a Tikhonov formulation, we infer the particle density fractions for each NBI energy for each NBI beam from synthetic measurements, resulting in six unknowns at TCV and 24 unknowns at W7-X. Additionally, we show that installing 40 LOS in each of 17 ports at W7-X, providing full beam coverage and almost full angle coverage, produces the highest quality reconstructions.
  • Experimental characterization of the active and passive fast-ion H-alpha emission in W7-X using FIDASIM
    (2024-02) Poloskei, Peter Zs; Geiger, B.; Jansen van Vuuren, A.; Äkäslompolo, S.; Ford, O.; Spanier, A.; Neelis, T. W.C.; McNeely, P.; Hartmann, D.; , W7-X Team
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    This paper presents the first results from the analysis of Balmer-alpha spectra at Wendelstein 7-X which contain the broad charge exchange emission from fast-ions. The measured spectra are compared to synthetic spectra predicted by the FIDASIM code, which has been supplied with the 3D magnetic fields from VMEC, 5D fast-ion distribution functions from ASCOT, and a realistic Neutral Beam Injection geometry including beam particle blocking elements. Detailed modeling of the beam emission shows excellent agreement between measured beam emission spectra and predictions. In contrast, modeling of beam halo radiation and Fast-Ion H-Alpha signals (FIDA) is more challenging due to strong passive contributions. While about 50% of the halo radiation can be attributed to passive signals from edge neutrals, the FIDA emission—in particular for an edge-localized line of sights—is dominated by passive emission. This is in part explained by high neutral densities in the plasma edge and in part by edge-born fast-ion populations as demonstrated by detailed modeling of the edge fast-ion distribution.
  • Experimental confirmation of efficient island divertor operation and successful neoclassical transport optimization in Wendelstein 7-X
    (2022-04-01) Pedersen, Thomas Sunn; Abramovic, Ivana; Agostinetti, P.; Torres, M. Agredano; Aekaeslompolo, S.; Belloso, J. Alcuson; Aleynikov, P.; Aleynikova, K.; Alhashimi, M.; Ali, A.; Allen, N.; Alonso, A.; Anda, G.; Andreeva, T.; Angioni, C.; Arkhipov, A.; Arnold, A.; Asad, W.; Ascasibar, E.; Aumeunier, M-H; Avramidis, K.; Aymerich, E.; Baek, S-G; Baehner, J.; Baillod, A.; Balden, M.; Baldzuhn, J.; Ballinger, S.; Banduch, M.; Bannmann, S.; Navarro, A. Banon; Barbui, T.; Beidler, C.; Belafdil, C.; Bencze, A.; Benndorf, A.; Beurskens, M.; Biedermann, C.; Biletskyi, O.; Blackwell, B.; Blatzheim, M.; Bluhm, T.; Boeckenhoff, D.; Bongiovi, G.; Borchardt, M.; Borodin, D.; Boscary, J.; Bosch, H.; Bosmann, T.; Boeswirth, B.; Boettger, L.; Bottino, A.; Bozhenkov, S.; Brakel, R.; Brandt, C.; Braeuer, T.; Braune, H.; Brezinsek, S.; Brunner, K.; Buller, S.; Burhenn, R.; Bussiahn, R.; Buttenschoen, B.; Buzas, A.; Bykov, Yuri; Calvo, Ivan; Mata, K. Camacho; Caminal; Cannas, B.; Cappa, A.; Carls, A.; Carovani, F.; Carr, M.; Carralero, D.; Carvalho, B.; Casas, J.; Castano-Bardawil, D.; Castejon, F.; Chaudhary, N.; Chelis; Chomiczewska, A.; Coenen, J. W.; Cole, M.; Cordella, F.; Corre, Y.; Crombe, K.; Cseh, G.; Csillag, B.; Damm, H.; Day, C.; de Baar, M.; De la Cal, E.; Degenkolbe, S.; Demby, A.; Denk, S.; Dhard, C.; Di Siena, A.; Dinklage, A.; Dittmar, T.; Dreval, M.; Drevlak, M.; Drewelow, P.; Drews, P.; Dunai, D.; Edlund, E.; Effenberg, F.; Ehrke, G.; Endler, M.; Ennis, D. A.; Escoto, F. J.; Estrada, T.; Fable, E.; Fahrenkamp, N.; Fanni, A.; Faustin, J.; Fellinger, J.; Feng, Y.; Figacz, W.; Flom, E.; Ford, O.; Fornal, T.; Frerichs, H.; Freundt, S.; Fuchert, G.; Fukuyama, M.; Fullenbach, F.; Gantenbein, G.; Gao, Y.; Garcia, K.; Regana, J. M. Garcia; Garcia-Cortes; Gaspar, J.; Gates, D. A.; Geiger, J.; Geiger, B.; Giudicotti, L.; Gonzalez, A.; Goriaev, A.; Gradic, D.; Grahl, M.; Graves, J. P.; Green, J.; Grelier, E.; Greuner, H.; Gross, S.; Grote, H.; Groth, M.; Gruca, M.; Grulke, O.; Gruen, M.; Arnaiz, J. Guerrero; Guenter, S.; Haak; Haas, M.; Hacker, P.; Hakola, A.; Hallenbert, A.; Hammond, K.; Han, X.; Hansen, S. K.; Harris, J. H.; Hartfuss, H.; Hartmann, D.; Hathiramani, D.; Hatzky, R.; Hawke, J.; Hegedus, S.; Hein, B.; Heinemann, B.; Helander, P.; Henneberg, S.; Hergenhahn, U.; Hidalgo, C.; Hindenlang, F.; Hirsch, M.; Hoefel, U.; Hollfeld, K. P.; Holtz, A.; Hopf, D.; Hoeschen, D.; Houry, M.; Howard, J.; Huang, X.; Hubeny, M.; Hudson, S.; Ida, K.; Igitkhanov, Y.; Igochine, Valentin; Illy, S.; Ionita-Schrittwieser, C.; Isobe, M.; Jablonski, S.; Jagielski, B.; Jakubowski, M.; Jansen van Vuuren, Anton; Jelonnek, J.; Jenko, F.; Jensen, T.; Jenzsch, H.; Junghanns, P.; Kaczmarczyk, J.; Kallmeyer, J.; Kamionka, U.; Kandler, M.; Kasilov, S.; Kazakov, Y.; Kennedy, D.; Kharwandikar, A.; Khokhlov, M.; Kiefer, C.; Killer, C.; Kirschner, A.; Kleiber, R.; Klinger, T.; Klose, S.; Knauer, J.; Knieps, A.; Koechl, F.; Kocsis, G.; Kolesnichenko, Ya; Koenies, A.; Koenig, R.; Kontula, J.; Kornejew, P.; Koschinsky, J.; Kozulia, M. M.; Kraemer-Flecken, A.; Krampitz, R.; Krause, M.; Krawczyk, N.; Kremeyer, T.; Krier, L.; Kriete, D. M.; Krychowiak, M.; Ksiazek, I.; Kubkowska, M.; Kuczynski, M.; Kuehner, G.; Kumar, A.; Kurki-Suonio, T.; Kwak, S.; Landreman, M.; Lang, P. T.; Langenberg, A.; Laqua, H. P.; Laqua, H.; Laube, R.; Lazerson, S.; Lewerentz, M.; Li, C.; Liang, Y.; Linsmeier, Ch; Lion, J.; Litnovsky, A.; Liu, S.; Lobsien, J.; Loizu, J.; Lore, J.; Lorenz, A.; Losada, U.; Louche, F.; Lunsford, R.; Lutsenko, VN; Machielsen, M.; Mackel, F.; Maisano-Brown, J.; Maj, O.; Makowski, D.; Manduchi, G.; Maragkoudakis, E.; Marchuk, O.; Marsen, S.; Martines, E.; Martinez-Fernandez, J.; Marushchenko, M.; Masuzaki, S.; Maurer, D.; Mayer, M.; McCarthy, K. J.; Mccormack, O.; McNeely, P.; Meister, H.; Mendelevitch, B.; Mendes, S.; Merlo, A.; Messian, A.; Mielczarek, A.; Mishchenko, O.; Missal, B.; Mitteau, R.; Moiseenko, V. E.; Mollen, A.; Moncada, Victor; Moennich, T.; Morisaki, T.; Moseev, D.; Motojima, G.; Mulas, S.; Mulsow, M.; Nagel, M.; Naujoks, D.; Naulin, Volker; Neelis, T.; Neilson, H.; Neu, R.; Neubauer, O.; Neuner, U.; Nicolai, D.; Nielsen, S. K.; Niemann, H.; Nishiza, T.; Nishizawa, T.; Nuehrenberg, C.; Ochoukov, R.; Oelmann, J.; Offermanns, G.; Ogawa, K.; Okamura, S.; Oelmanns, J.; Ongena, J.; Oosterbeek, J.; Otte, M.; Pablant, N.; Panadero Alvarez, N.; Pandey, A.; Pasch, E.; Pavlichenko, R.; Pavone, A.; Pawelec, E.; Pechstein, G.; Pelka, G.; Perseo, Valeria; Peterson, B.; Pilopp, D.; Pingel, S.; Pisano, F.; Plockl, B.; Plunk, G.; Poloskei, P.; Pompe, B.; Popov, A.; Porkolab, M.; Proll, J.; Pueschel, M. J.; Puiatti, M-E; Sitjes, A. Puig; Purps, F.; Rahbarnia, K.; Rasmussen, J.; Reiman, A.; Reimold, F.; Reisner, M.; Reiter, D.; Richou, M.; Riedl, R.; Riemann, J.; Risse, K.; Roberg-Clark, G.; Rohde, Volker; Romazanov, J.; Rondeshagen, D.; Rong, P.; Rudischhauser, L.; Rummel, T.; Rummel, K.; Runov, A.; Rust, N.; Ryc, L.; Salembier, P.; Salewski, M.; Sanchez, E.; Satake, S.; Satheeswaran, G.; Schacht, J.; Scharff, E.; Schauer, F.; Schilling, J.; Schlisio, G.; Schmid, K.; Schmitt, J.; Schmitz, O.; Schneider, W.; Schneider, M.; Schneider, P.; Schrittwieser, R.; Schroeder, T.; Schroeder, M.; Schroeder, R.; Schweer, B.; Schwoerer, D.; Scott, E.; Shanahan, B.; Sias, G.; Sichta, P.; Singer, M.; Sinha, P.; Sipilä, S.; Slaby, C.; Sleczka, M.; Smith, H.; Smoniewski, J.; Sonnendrucker, E.; Spolaore, M.; Spring, A.; Stadler, R.; Stange, T.; Stepanov, A.Y.; Stephey, L.; Stober, J.; Stroth, U.; Strumberger, E.; Suzuki, C.; Suzuki, Y.; Svensson, J.; Szabolics, T.; Szepesi, T.; Szucs, M.; Tabares, F. L.; Tamura, N.; Tancetti, A.; Tantos, C.; Terry, J.; Thienpondt, H.; Thomsen, H.; Thumm, M.; Travere, J. M.; Traverso, P.; Tretter, J.; Trier, E.; Mora, H. Trimino; Tsujimura, T.; Turkin, Y.; Tykhyi, A.; Unterberg, B.; van Eeten, P.; van Milligen, B. Ph; van Schoor, M.; Vano, L.; Varoutis, S.; Vecsei, M.; Vela, L.; Velasco, J. L.; Vervier, M.; Vianello, N.; Viebke, H.; Vilbrandt, R.; Vogt, N.; Volkhausen, C.; von Stechow, A.; Wagner, F.; Wang, E.; Wang, H.; Warmer, F.; Wauters, T.; Wegener, L.; Wegner, T.; Weir, G.; Wenzel, U.; White, A.; Wilde, F.; Wilms, F.; Windisch, T.; Winkler, M.; Winter, A.; Winters, Victoria; Wolf, R.; Wright, A. M.; Wurden, G. A.; Xanthopoulos, P.; Xu, S.; Yamada, H.; Yamaguchi, H.; Yokoyama, M.; Yoshinuma, M.; Yu, Q.; Zamanov, M.; Zanini, M.; Zarnstorff, M.; Zhang, D.; Zhou, S.; Zhu, J.; Zhu, C.; Zilker, M.; Zocco, A.; Zohm, H.; Zoletnik, S.; Zsuga, L.; Vogel, G.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    We present recent highlights from the most recent operation phases of Wendelstein 7-X, the most advanced stellarator in the world. Stable detachment with good particle exhaust, low impurity content, and energy confinement times exceeding 100 ms, have been maintained for tens of seconds. Pellet fueling allows for plasma phases with reduced ion-temperature-gradient turbulence, and during such phases, the overall confinement is so good (energy confinement times often exceeding 200 ms) that the attained density and temperature profiles would not have been possible in less optimized devices, since they would have had neoclassical transport losses exceeding the heating applied in W7-X. This provides proof that the reduction of neoclassical transport through magnetic field optimization is successful. W7-X plasmas generally show good impurity screening and high plasma purity, but there is evidence of longer impurity confinement times during turbulence-suppressed phases.
  • Feasibility of neutral particle analysis for fast-ion measurements at W7-X
    (2022-01) Bannmann, S.; Bozhenkov, S.; Äkäslompolo, S.; Poloskei, P.; Schneider, W.; Ford, O.; Wolf, R. C.; , W7-X Team
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    A preliminary study investigating capabilities of a planned but not yet installed neutral particle analyzer (NPA) [1,2] system combined with a diagnostic neutral beam at Wendelstein 7-X (W7-X) [3] is presented. Additionally two NPAs viewing the neutral beam injection (NBI) [4] source 8 beam and using it as neutral source are studied. The main focus is laid on what information about NBI fast-ion slowing down distributions can be inferred from active NPA measurements when altering the magnetic configuration, plasma β, density, electron temperature or radial electric field. For an order of magnitude estimation of the passive signal a model for penetration of neutral hydrogen recycling from the first wall is implemented. For the active signal a diagnostic neutral beam injector was simulated using FIDASIM [5]. The fast-ion slowing down distributions were calculated with ASCOT [6]. The synthetic NPA signal is found in general to be sensitive to changes in the fast-ion distribution function. Distinct features can be seen in the high energy active signal in the high-mirror configuration when changing β, especially, when looking at deeply trapped fast particles. However, for the initially planned installation geometry of the NPA diagnostic most fast-ion distributions exhibit only small differences in the magnitude and especially shape. In a high density case in the standard magnetic configuration with a central β of 8%, the fast-ion density in the core region is too low to provide a measurable flux of charge exchanged neutrals. The passive signal from the inner plasma regions is found to be negligible compared to the active signal.
  • Overview of ASDEX Upgrade results
    (2017-10) Aguiam, D.; Aho-Mantila, L.; Angioni, C.; Arden, N.; Parra, R. Arredondo; Asunta, O.; de Baar, M.; Balden, M.; Behler, K.; Bergmann, A.; Bernardo, J.; Bernert, M.; Beurskens, M.; Biancalani, A.; Bilato, R.; Birkenmeier, G.; Bobkov, V.; Bock, A.; Bogomolov, A.; Bolzonella, T.; Boeswirth, B.; Bottereau, C.; Bottino, A.; van den Brand, H.; Brezinsek, S.; Brida, D.; Brochard, F.; Bruhn, C.; Buchanan, J.; Buhler, A.; Burckhart, A.; Cambon-Silva, D.; Camenen, Y.; Carvalho, P.; Carrasco, G.; Cazzaniga, C.; Carr, M.; Carralero, D.; Casali, L.; Castaldo, C.; Cavedon, M.; Challis, C.; Chankin, A.; Chapman, I.; Clairet, F.; Classen, I.; Coda, S.; Coelho, R.; Coenen, J. W.; Colas, L.; Conway, G.; Costea, S.; Coster, D. P.; Croci, G.; Cseh, G.; Czarnecka, A.; D'Arcangelo, O.; Day, C.; Delogu, R.; de Marne, P.; Denk, S.; Denner, P.; Dibon, M.; D'Inca, R.; Di Siena, A.; Douai, D.; Drenik, A.; Drube, R.; Dunne, M.; Duval, B. P.; Dux, R.; Eich, T.; Elgeti, S.; Engelhardt, K.; Erdos, B.; Erofeev, I.; Esposito, B.; Fable, E.; Faitsch, M.; Fantz, U.; Faugel, H.; Felici, F.; Fietz, S.; Figueredo, A.; Fischer, R.; Ford, O.; Frassinetti, L.; Freethy, S.; Froeschle, M.; Fuchert, G.; Fuchs, J. C.; Fuenfgelder, H.; Galazka, K.; Galdon-Quiroga, J.; Gallo, A.; Gao, Y.; Garavaglia, S.; Garcia-Munoz, M.; Geiger, B.; Cianfarani, C.; Giannone, L.; Giovannozzi, E.; Gleason-Gonzalez, C.; Gloeggler, S.; Gobbin, M.; Goerler, T.; Goodman, T.; Gorini, G.; Gradic, D.; Graeter, A.; Granucci, G.; Greuner, H.; Griener, M.; Groth, M.; Gude, A.; Guenter, S.; Guimarais, L.; Haas, G.; Hakola, A. H.; Ham, C.; Happel, T.; Harrison, J.; Hatch, D.; Hauer, V.; Hayward, T.; Heinemann, B.; Heinzel, S.; Hellsten, T.; Henderson, S.; Hennequin, P.; Herrmann, A.; Heyn, E.; Hitzler, F.; Hobirk, J.; Hoelzl, M.; Hoeschen, T.; Holm, J. H.; Hopf, C.; Hoppe, F.; Horvath, L.; Houben, A.; Huber, A.; Igochine, V.; Ilkei, T.; Ivanova-Stanik, I.; Jacob, W.; Jacobsen, A. S.; Jacquot, J.; Janky, F.; Jardin, A.; Jaulmes, F.; Jenko, F.; Jensen, T.; Joffrin, E.; Kaesemann, C.; Kallenbach, A.; Kalvin, S.; Kantor, M.; Kappatou, A.; Kardaun, O.; Karhunen, J.; Kasilov, S.; Kernbichler, W.; Kim, D.; Kimmig, S.; Kirk, A.; Klingshirn, H. -J.; Koch, F.; Kocsis, G.; Koehn, A.; Kraus, M.; Krieger, K.; Krivska, A.; Kraemr-Flecken, A.; Kurki-Suonio, T.; Kurzan, B.; Lackner, K.; Laggner, F.; Lang, P. T.; Lauber, P.; Lazanyi, N.; Lazaros, A.; Lebschy, A.; Li, L.; Li, M.; Liang, Y.; Lipschultz, B.; Liu, Y.; Lohs, A.; Luhmann, N. C.; Lunt, T.; Lyssoivan, A.; Madsen, J.; Maier, H.; Maj, O.; Mailloux, J.; Maljaars, E.; Manas, P.; Mancini, A.; Manhard, A.; Manso, M. -E.; Mantica, P.; Mantsinen, M.; Manz, P.; Maraschek, M.; Martens, C.; Martin, P.; Marrelli, L.; Martitsch, A.; Mastrostefano, S.; Mayer, A.; Mayer, M.; Mazon, D.; McCarthy, P. J.; McDermott, R.; Meisl, G.; Meister, H.; Medvedeva, A.; Merkel, P.; Merkel, R.; Merle, A.; Mertens, V.; Meshcheriakov, D.; Meyer, H.; Meyer, O.; Miettunen, J.; Milanesio, D.; Mink, F.; Mlynek, A.; Monaco, F.; Moon, C.; Nazikian, R.; Nemes-Czopf, A.; Neu, G.; Neu, R.; Nielsen, A. H.; Nielsen, S. K.; Nikolaeva, V.; Nocente, M.; Noterdaeme, J. -M.; Nowak, S.; Oberkofler, M.; Oberparleiter, M.; Ochoukov, R.; Odstrcil, T.; Olsen, J.; Orain, F.; Palermo, F.; Papp, G.; Perez, I. Paradela; Pautasso, G.; Enzel, F.; Petersson, P.; Pinzon, J.; Piovesan, P.; Piron, C.; Plaum, B.; Ploeckl, B.; Plyusnin, V.; Pokol, G.; Poli, E.; Porte, L.; Potzel, S.; Prisiazhniuk, D.; Puetterich, T.; Ramisch, M.; Rapson, C.; Rasmussen, J.; Raupp, G.; Refy, D.; Reich, M.; Reimold, F.; Ribeiro, T.; Riedl, R.; Rittich, D.; Rocchi, G.; Rodriguez-Ramos, M.; Rohde, V.; Ross, A.; Rott, M.; Rubel, M.; Ryan, D.; Ryter, F.; Saarelma, S.; Salewski, M.; Salmi, A.; Sanchis-Sanchez, L.; Santos, G.; Santos, J.; Sauter, O.; Scarabosio, A.; Schall, G.; Schmid, K.; Schmitz, O.; Schneider, P. A.; Schneller, M.; Schrittwieser, R.; Schubert, M.; Schwarz-Selinger, T.; Schweinzer, J.; Scott, B.; Sehmer, T.; Sertoli, M.; Shabbir, A.; Shalpegin, A.; Shao, L.; Sharapov, S.; Siccinio, M.; Sieglin, B.; Sigalov, A.; Silva, A.; Silva, C.; Simon, P.; Simpson, J.; Snicker, A.; Sommariva, C.; Sozzi, C.; Spolaore, M.; Stejner, M.; Stober, J.; Stobbe, F.; Stroth, U.; Strumberger, E.; Suarez, G.; Sugiyama, K.; Sun, H. -J.; Suttrop, W.; Szepesi, T.; Tal, B.; Tala, T.; Tardini, G.; Tardocchi, M.; Terranova, D.; Tierens, W.; Told, D.; Tudisco, O.; Trevisan, G.; Treutterer, W.; Trier, E.; Tripsky, M.; Valisa, M.; Valovic, M.; Vanovac, B.; Varela, P.; Varoutis, S.; Verdoolaege, G.; Vezinet, D.; Vianello, N.; Vicente, J.; Vierle, T.; Viezzer, E.; von Toussaint, U.; Wagner, D.; Wang, N.; Wang, X.; Weidl, M.; Weiland, M.; White, A. E.; Willensdorfer, M.; Wiringer, B.; Wischmeier, M.; Wolf, R.; Wolfrum, E.; Xiang, L.; Yang, Q.; Yang, Z.; Yu, Q.; Zagorski, R.; Zammuto, I.; Zarzoso, D.; Zhang, W.; van Zeeland, M.; Zehetbauer, T.; Zilker, M.; Zoletnik, S.; Zohm, H.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The ASDEX Upgrade (AUG) programme is directed towards physics input to critical elements of the ITER design and the preparation of ITER operation, as well as addressing physics issues for a future DEMO design. Since 2015, AUG is equipped with a new pair of 3-strap ICRF antennas, which were designed for a reduction of tungsten release during ICRF operation. As predicted, a factor two reduction on the ICRF-induced W plasma content could be achieved by the reduction of the sheath voltage at the antenna limiters via the compensation of the image currents of the central and side straps in the antenna frame. There are two main operational scenario lines in AUG. Experiments with low collisionality, which comprise current drive, ELM mitigation/suppression and fast ion physics, are mainly done with freshly boronized walls to reduce the tungsten influx at these high edge temperature conditions. Full ELM suppression and non-inductive operation up to a plasma current of I-p = 0.8 MA could be obtained at low plasma density. Plasma exhaust is studied under conditions of high neutral divertor pressure and separatrix electron density, where a fresh boronization is not required. Substantial progress could be achieved for the understanding of the confinement degradation by strong D puffing and the improvement with nitrogen or carbon seeding. Inward/outward shifts of the electron density profile relative to the temperature profile effect the edge stability via the pressure profile changes and lead to improved/decreased pedestal performance. Seeding and D gas puffing are found to effect the core fueling via changes in a region of high density on the high field side (HFSHD). The integration of all above mentioned operational scenarios will be feasible and naturally obtained in a large device where the edge is more opaque for neutrals and higher plasma temperatures provide a lower collisionality. The combination of exhaust control with pellet fueling has been successfully demonstrated. High divertor enrichment values of nitrogen E-N >= 10 have been obtained during pellet injection, which is a prerequisite for the simultaneous achievement of good core plasma purity and high divertor radiation levels. Impurity accumulation observed in the all-metal AUG device caused by the strong neoclassical inward transport of tungsten in the pedestal is expected to be relieved by the higher neoclassical temperature screening in larger devices.
  • Overview of first Wendelstein 7-X high-performance operation
    (2019-11) Klinger, T.; Andreeva, T.; Bozhenkov, S.; Brandt, C.; Burhenn, R.; Buttenschoen, B.; Fuchert, G.; Geiger, B.; Grulke, O.; Laqua, H. P.; Pablant, N.; Rahbarnia, K.; Stange, T.; von Stechow, A.; Tamura, N.; Thomsen, H.; Turkin, Y.; Wegner, T.; Abramovic, Ivana; Aekaeslompolo, S.; Alcuson, J.; Aleynikov, P.; Aleynikova, K.; Ali, A.; Alonso, A.; Anda, G.; Ascasibar, E.; Baehner, J. P.; Baek, S. G.; Balden, M.; Baldzuhn, J.; Banduch, M.; Barbui, T.; Behr, W.; Beidler, C.; Benndorf, A.; Biedermann, C.; Biel, W.; Blackwell, B.; Blanco, E.; Blatzheim, M.; Ballinger, S.; Bluhm, T.; Boeckenhoff, D.; Boeswirth, B.; Boettger, L-G; Borchardt, M.; Borsuk, Mark; Boscary, J.; Bosch, H-S; Beurskens, M.; Brakel, R.; Brand, H.; Braeuer, T.; Braune, H.; Brezinsek, S.; Brunner, K-J; Bussiahn, R.; Bykov, I.; Cai, J.; Calvo, Iván; 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. J.; Cordella, F.; Cseh, G.; Czarnecka, A.; Czerski, K.; Czerwinski, M.; Czymek, G.; da Molin, A.; da Silva, A.; Damm, H.; de la Pena, A.; Degenkolbe, S.; Dhard, C. P.; Dibon, M.; Dinklage, A.; Dittmar, T.; Drevlak, M.; Drewelow, P.; Drews, P.; Durodie, F.; Edlund, E.; van Eeten, P.; 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.; Ford, O.; Fornal, T.; Frerichs, H.; Freund, A.; Funaba, T.; Galkowski, A.; Gantenbein, G.; Gao, Y.; Garcia Regana, J.; Gates, D.; Geiger, J.; Giannella, R.; 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.; Hartmann, D.; Hathiramani, D.; Hein, B.; Heinemann, B.; Helander, P.; Henneberg, S.; Henkel, M.; Hernandez Sanchez, J.; Hidalgo, C.; Hirsch, M.; Hollfeld, K. P.; Hoefel, U.; Hoelting, A.; Hoeschen, 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.; Kazakov, Y. O.; Kenmochi, N.; Killer, C.; Kirschner, A.; Kleiber, R.; Knauer, J.; Knaup, M.; Knieps, A.; Kobarg, T.; Kocsis, G.; Koechl, F.; Kolesnichenko, Y.; Koenies, A.; Koenig, R.; Kornejew, P.; Koschinsky, J-P; Koester, F.; Kraemer, M.; Krampitz, R.; Kraemer-Flecken, A.; Krawczyk, N.; Kremeyer, T.; Krom, J.; Krychowiak, M.; Ksiazek, I.; Kubkowska, M.; Kuehner, G.; Kurki-Suonio, T.; Kurz, P. A.; Kwak, S.; Landreman, M.; Lang, P.; Lang, R.; Langenberg, A.; Langish, S.; Laqua, H.; Laube, R.; Lazerson, S.; Lechte, C.; Lennartz, M.; Leonhardt, W.; Li, C.; Li, Y.; Liang, Y.; Linsmeier, C.; Liu, S. C.; Lobsien, J-F; Loesser, D.; Cisquella, J. Loizu; Lore, J.; Lorenz, A.; Losert, M.; Lucke, A.; Lumsdaine, A.; Lutsenko, VN; 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, Victor; Moennich, 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.; Nocentini, R.; Nuehrenberg, C.; Nuehrenberg, J.; Obermayer, S.; Offermanns, G.; Ogawa, K.; Oelmanns, J.; Ongena, J.; Oosterbeek, J. W.; Orozco, G.; Otte, M.; Pacios Rodriguez, L.; Panadero, N.; Panadero Alvarez, N.; Papenfuss, D.; Paqay, S.; Pasch, E.; Pavone, A.; Pawelec, E.; Pedersen, T. S.; Pelka, G.; Perseo, Valeria; Peterson, B.; Pilopp, D.; Pingel, S.; Pisano, F.; Plaum, B.; Plunk, G.; Poeloeskei, P.; Porkolab, M.; Proll, J.; Puiatti, M-E; Sitjes, A. Puig; Purps, F.; Rack, M.; Recsei, S.; Reiman, A.; Reimold, F.; Reiter, D.; Remppel, F.; Renard, S.; Riedl, R.; Riemann, J.; Risse, K.; Rohde, Volker; Roehlinger, H.; Rome, 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, E.; Sano, F.; Satake, S.; Schacht, J.; Satheeswaran, G.; Schauer, F.; Scherer, T.; Schilling, J.; Schlaich, A.; Schlisio, G.; Schluck, F.; Schlueter, K-H; Schmitt, J.; Schmitz, H.; Schmitz, O.; Schmuck, S.; Schneider, M.; Schneider, W.; Scholz, P.; Schrittwieser, R.; Schröder, Michael; Schroeder, T.; Schroeder, R.; Schumacher, H.; Schweer, B.; Scott, E.; 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.; Svensson, J.; Szabo, Susanne J.; Szabolics, T.; Szepesi, T.; Szokefalvi-Nagy, Z.; Tancetti, A.; Terry, J.; Thomas, J.; Thumm, M.; Travere, J. M.; Traverso, P.; Tretter, J.; Mora, H. Trimino; Tsuchiya, H.; Tsujimura, T.; Tulipan, S.; Unterberg, B.; Vakulchyk, I.; Valet, S.; Vano, L.; van Milligen, B.; van Vuuren, A. J.; Vela, L.; Velasco, J-L; Vergote, M.; Vervier, M.; Vianello, N.; Viebke, H.; Vilbrandt, R.; Vorkoeper, A.; Wadle, S.; Wagner, F.; Wang, E.; Wang, N.; Wang, Z.; Warmer, F.; Wauters, T.; 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, Victoria; Wolf, S.; Wolf, R. C.; Wright, A.; Wurden, G.; Xanthopoulos, P.; Yamada, H.; Yamada, Ichihiro; Yasuhara, R.; Yokoyama, M.; Zanini, M.; Zarnstorff, M.; Zeitler, A.; Zhang, D.; Zhang, H.; Zhu, J.; Zilker, M.; Zocco, A.; Zoletnik, S.; Zuin, M.
     A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
    The optimized superconducting stellarator device Wendelstein 7-X (with major radius R = 5.5 m, minor radius a = 0.5 m, and 30 m(3) plasma volume) restarted operation after the assembly of a graphite heat shield and 10 inertially cooled island divertor modules. This paper reports on the results from the first high-performance plasma operation. Glow discharge conditioning and ECRH conditioning discharges in helium turned out to be important for density and edge radiation control. Plasma densities of 1-4.5 x 10(19) m(-3) with central electron temperatures 5-10 keV were routinely achieved with hydrogen gas fueling, frequently terminated by a radiative collapse. In a first stage, plasma densities up to 1.4 x 10(20) m(-3) were reached with hydrogen pellet injection and helium gas fueling. Here, the ions are indirectly heated, and at a central density of 8 . 10(19 )m(-3) a temperature of 3.4 keV with T-e/T-i = 1 was transiently accomplished, which corresponds to nT(i)(0)tau(E) = 6.4 x 10(19) keV s m(-3) with a peak diamagnetic energy of 1.1 MJ and volume-averaged normalized plasma pressure = 1.2%. The routine access to high plasma densities was opened with boronization of the first wall. After boronization, the oxygen impurity content was reduced by a factor of 10, the carbon impurity content by a factor of 5. The reduced (edge) plasma radiation level gives routinely access to higher densities without radiation collapse, e.g. well above 1 x 10(20) m(-2) line integrated density and T-e = T-i = 2 keV central temperatures at moderate ECRH power. Both X2 and O2 mode ECRH schemes were successfully applied. Core turbulence was measured with a phase contrast imaging diagnostic and suppression of turbulence during pellet injection was observed.
  • Overview of physics studies on ASDEX Upgrade
    (2019-07-22) Meyer, H.; Angioni, C.; Albert, C. G.; Arden, Nils; Arredondo Parra, R.; Asunta, O.; De Baar, M.; Balden, M.; Bandaru, V.; Behler, K.; Bergmann, A.; Bernardo, J.; Bernert, M.; Biancalani, A.; Bilato, R.; Birkenmeier, G.; Blanken, T. C.; Bobkov, V.; Bock, A.; Bolzonella, T.; Bortolon, A.; Böswirth, B.; Bottereau, C.; Bottino, A.; Van Den Brand, H.; Brezinsek, S.; Brida, D.; Brochard, F.; Bruhn, C.; Buchanan, J.; Buhler, A.; Burckhart, A.; Camenen, Y.; Carlton, D.; Carr, M.; Carralero, D.; Castaldo, C.; Cavedon, M.; Cazzaniga, C.; Ceccuzzi, S.; Challis, C.; Chankin, A.; Chapman, S.; Cianfarani, C.; Clairet, F.; Coda, S.; Coelho, R.; Coenen, J. W.; Colas, L.; Conway, G. D.; Costea, S.; Coster, D. P.; Cote, T. B.; Creely, A.; Croci, G.; Cseh, G.; Czarnecka, A.; Cziegler, I.; D'Arcangelo, O.; David, P.; Day, C.; Delogu, R.; De Marné, P.; Denk, S. S.; Denner, P.; Dibon, M.; Di Siena, A.; Douai, D.; Drenik, A.; Drube, R.; Dunne, M.; Duval, B. P.; Dux, R.; Eich, T.; Elgeti, S.; Engelhardt, K.; Erdös, B.; Erofeev, I.; Esposito, B.; Fable, E.; Faitsch, M.; Fantz, U.; Faugel, H.; Faust, I.; Felici, F.; Ferreira, J.; Fietz, S.; Figuereido, A.; Fischer, R.; Ford, O.; Frassinetti, L.; Freethy, S.; Fröschle, M.; Fuchert, G.; Fuchs, J. C.; Fünfgelder, H.; Galazka, K.; Galdon-Quiroga, J.; Gallo, A.; Gao, Y.; Garavaglia, S.; Garcia-Carrasco, A.; Garcia-Munoz, M.; Geiger, B.; Giannone, L.; Gil, L.; Giovannozzi, E.; Gleason-González, C.; Glöggler, S.; Gobbin, M.; Görler, T.; Gomez Ortiz, I.; Gonzalez Martin, J.; Goodman, T.; Gorini, G.; Gradic, D.; Grater, A.; Granucci, G.; Greuner, H.; Griener, M.; Groth, M.; Gude, A.; Günter, Sibylle; Guimarais, L.; Haas, G.; Hakola, A. H.; Ham, C.; Happel, T.; Den Harder, N.; Harrer, G. F.; Harrison, J.; Hauer, V.; Hayward-Schneider, T.; Hegna, C. C.; Heinemann, B.; Heinzel, S.; Hellsten, T.; Henderson, S.; Hennequin, P.; Herrmann, A.; Heyn, M. F.; Heyn, E.; Hitzler, F.; Hobirk, J.; Höfler, K.; Hölzl, M.; Höschen, T.; Holm, J. H.; Hopf, C.; Hornsby, W. A.; Horvath, L.; Houben, A.; Huber, A.; Igochine, V.; Ilkei, T.; Ivanova-Stanik, I.; Jacob, W.; Jacobsen, A. S.; Janky, F.; Jansen Van Vuuren, A.; Jardin, A.; Jaulmes, F.; Jenko, F.; Jensen, T.; Joffrin, E.; Kasemann, C. P.; Kallenbach, A.; Kálvin, S.; Kantor, M.; Kappatou, A.; Kardaun, O.; Karhunen, J.; Kasilov, S.; Kazakov, Y.; Kernbichler, W.; Kirk, A.; Kjer Hansen, S.; Klevarova, V.; Kocsis, G.; Köhn, A.; Koubiti, M.; Krieger, K.; Krivska, A.; Kramer-Flecken, A.; Kudlacek, O.; Kurki-Suonio, T.; Kurzan, B.; Labit, B.; Lackner, K.; Laggner, F.; Lang, P. T.; Lauber, P.; Lebschy, A.; Leuthold, N.; Li, M.; Linder, O.; Lipschultz, B.; Liu, Fukun; Liu, Y. Q.; Lohs, A.; Lu, Z.; Luda Di Cortemiglia, T.; Luhmann, N. C.; Lunsford, R.; Lunt, T.; Lyssoivan, A.; Maceina, T.; Madsen, J.; Maggiora, R.; Maier, H.; Maj, O.; Mailloux, J.; Maingi, R.; Maljaars, E.; Manas, P.; Mancini, A.; Manhard, A.; Manso, M. E.; Mantica, P.; Mantsinen, M.; Manz, P.; Maraschek, M.; Martens, C.; Martin, P.; Marrelli, L.; Martitsch, A.; Mayer, M.; Mazon, D.; McCarthy, P. J.; McDermott, R.; Meister, H.; Medvedeva, A.; Merkel, R.; Merle, A.; Mertens, V.; Meshcheriakov, D.; Meyer, O.; Miettunen, J.; Milanesio, D.; Mink, F.; Mlynek, A.; Monaco, F.; Moon, C.; Nabais, F.; Nemes-Czopf, A.; Neu, G.; Neu, R.; Nielsen, A. H.; Nielsen, S. K.; Nikolaeva, V.; Nocente, M.; Noterdaeme, J. M.; Novikau, I.; Nowak, S.; Oberkofler, M.; Oberparleiter, M.; Ochoukov, R.; Odstrcil, T.; Olsen, J.; Orain, F.; Palermo, F.; Pan, O.; Papp, G.; Paradela Perez, I.; Pau, A.; Pautasso, G.; Penzel, F.; Petersson, P.; Pinzón Acosta, J.; Piovesan, P.; Piron, C.; Pitts, R.; Plank, U.; Plaum, B.; Ploeckl, B.; Plyusnin, V.; Pokol, G.; Poli, E.; Porte, L.; Potzel, S.; Prisiazhniuk, D.; Pütterich, T.; Ramisch, M.; Rasmussen, J.; Rattá, G. A.; Ratynskaia, S.; Raupp, G.; Ravera, G. L.; Réfy, D.; Reich, M.; Reimold, F.; Reiser, D.; Ribeiro, T.; Riesch, J.; Riedl, R.; Rittich, D.; Rivero-Rodriguez, J. F.; Rocchi, G.; Rodriguez-Ramos, M.; Rohde, V.; Ross, A.; Rott, M.; Rubel, M.; Ryan, D.; Ryter, F.; Saarelma, S.; Salewski, M.; Salmi, A.; Sanchis-Sanchez, L.; Santos, J.; Sauter, O.; Scarabosio, A.; Schall, G.; Schmid, K.; Schmitz, O.; Schneider, P. A.; Schrittwieser, R.; Schubert, M.; Schwarz-Selinger, T.; Schweinzer, J.; Scott, B.; Sehmer, T.; Seliunin, E.; Sertoli, M.; Shabbir, A.; Shalpegin, A.; Shao, Linming; Sharapov, S.; Sias, G.; Siccinio, M.; Sieglin, B.; Sigalov, A.; Silva, A.; Silva, C.; Silvagni, D.; Simon, P.; Simpson, J.; Smigelskis, E.; Snicker, A.; Sommariva, C.; Sozzi, C.; Spolaore, M.; Stegmeir, A.; Stejner, M.; Stober, J.; Stroth, U.; Strumberger, E.; Suarez, G.; Sun, H. J.; Suttrop, W.; Sytova, E.; Szepesi, T.; Tál, B.; Tala, T.; Tardini, G.; Tardocchi, M.; Teschke, M.; Terranova, D.; Tierens, W.; Thorén, E.; Told, D.; Tolias, P.; Tudisco, O.; Treutterer, W.; Trier, E.; Tripský, M.; Valisa, M.; Valovic, M.; Vanovac, B.; Van Vugt, D.; Varoutis, S.; Verdoolaege, G.; Vianello, N.; Vicente, J.; Vierle, T.; Viezzer, E.; Von Toussaint, U.; Wagner, D.; Wang, N.; Wang, Xianqu; Weiland, M.; White, A. E.; Wiesen, S.; Willensdorfer, M.; Wiringer, B.; Wischmeier, M.; Wolf, R.; Wolfrum, E.; Xiang, L.; Yang, Q.; Yang, Z.; Yu, Q.; Zagórski, R.; Zammuto, I.; Zhang, Wei; Van Zeeland, M.; Zehetbauer, T.; Zilker, M.; Zoletnik, S.; Zohm, H.
     A2 Katsausartikkeli tieteellisessä aikakauslehdessä
    The ASDEX Upgrade (AUG) programme, jointly run with the EUROfusion MST1 task force, continues to significantly enhance the physics base of ITER and DEMO. Here, the full tungsten wall is a key asset for extrapolating to future devices. The high overall heating power, flexible heating mix and comprehensive diagnostic set allows studies ranging from mimicking the scrape-off-layer and divertor conditions of ITER and DEMO at high density to fully non-inductive operation (q 95 = 5.5, ) at low density. Higher installed electron cyclotron resonance heating power 6 MW, new diagnostics and improved analysis techniques have further enhanced the capabilities of AUG. Stable high-density H-modes with MW m-1 with fully detached strike-points have been demonstrated. The ballooning instability close to the separatrix has been identified as a potential cause leading to the H-mode density limit and is also found to play an important role for the access to small edge-localized modes (ELMs). Density limit disruptions have been successfully avoided using a path-oriented approach to disruption handling and progress has been made in understanding the dissipation and avoidance of runaway electron beams. ELM suppression with resonant magnetic perturbations is now routinely achieved reaching transiently . This gives new insight into the field penetration physics, in particular with respect to plasma flows. Modelling agrees well with plasma response measurements and a helically localised ballooning structure observed prior to the ELM is evidence for the changed edge stability due to the magnetic perturbations. The impact of 3D perturbations on heat load patterns and fast-ion losses have been further elaborated. Progress has also been made in understanding the ELM cycle itself. Here, new fast measurements of and E r allow for inter ELM transport analysis confirming that E r is dominated by the diamagnetic term even for fast timescales. New analysis techniques allow detailed comparison of the ELM crash and are in good agreement with nonlinear MHD modelling. The observation of accelerated ions during the ELM crash can be seen as evidence for the reconnection during the ELM. As type-I ELMs (even mitigated) are likely not a viable operational regime in DEMO studies of 'natural' no ELM regimes have been extended. Stable I-modes up to have been characterised using -feedback. Core physics has been advanced by more detailed characterisation of the turbulence with new measurements such as the eddy tilt angle - measured for the first time - or the cross-phase angle of and fluctuations. These new data put strong constraints on gyro-kinetic turbulence modelling. In addition, carefully executed studies in different main species (H, D and He) and with different heating mixes highlight the importance of the collisional energy exchange for interpreting energy confinement. A new regime with a hollow profile now gives access to regimes mimicking aspects of burning plasma conditions and lead to nonlinear interactions of energetic particle modes despite the sub-Alfvénic beam energy. This will help to validate the fast-ion codes for predicting ITER and DEMO.