Professor Felix Parra Diaz: Publications

Effects of misaligning the probe beam and magnetic field in Doppler backscattering measurements

45th EPS Conference on Plasma Physics, EPS 2018 2018-July (2018) 1436-1439

Authors:

VH Hall-Chen, FI Parra, JC Hillesheim

Optimized up-down asymmetry to drive fast intrinsic rotation in tokamaks

Nuclear Fusion Institute of Physics 58:2 (2017) 026003

Authors:

Justin R Ball, Felix I Parra, M Landreman, Michael A Barnes

Abstract:

Breaking the up-down symmetry of the tokamak poloidal cross-section can significantly increase the spontaneous rotation due to turbulent momentum transport. In this work, we optimize the shape of flux surfaces with both tilted elongation and tilted triangularity in order to maximize this drive of intrinsic rotation. Nonlinear gyrokinetic simulations demonstrate that adding optimally-tilted triangularity can double the momentum transport of a tilted elliptical shape. This work indicates that tilting the elongation and triangularity in an ITER-like device can reduce the energy transport and drive intrinsic rotation with an Alfv\'{e}n Mach number on the order of $1\%$. This rotation is four times larger than the rotation expected in ITER and is sufficient to stabilize MHD instabilities. It is shown that this optimal shape can be created using the shaping coils of several experiments.

Overview of progress in European medium sized tokamaks towards an integrated plasma-edge/wall solution a aIn the future we will refer to the author list of the paper as the EUROfusion MST1 Team.

Nuclear Fusion IOP Publishing 57:10 (2017) 102014

Authors:

H Meyer, T Eich, M Beurskens, S Coda, A Hakola, P Martin, J Adamek, M Agostini, D Aguiam, J Ahn, L Aho-Mantila, R Akers, R Albanese, R Aledda, E Alessi, S Allan, D Alves, R Ambrosino, L Amicucci, H Anand, G Anastassiou, Y Andrèbe, C Angioni, G Apruzzese, M Ariola, H Arnichand, W Arter, A Baciero, M Barnes, L Barrera, R Behn, A Bencze, J Bernardo, M Bernert, P Bettini, P Bilková, W Bin, G Birkenmeier, JPS Bizarro, P Blanchard, T Blanken, M Bluteau, V Bobkov, O Bogar, P Böhm, T Bolzonella, L Boncagni, A Botrugno, C Bottereau, F Bouquey, C Bourdelle, S Brémond, S Brezinsek, D Brida, F Brochard, J Buchanan, H Bufferand, P Buratti, P Cahyna, G Calabrò, Y Camenen, R Caniello, B Cannas, A Canton, A Cardinali, D Carnevale, M Carr, D Carralero, P Carvalho, L Casali, C Castaldo, F Castejón, R Castro, F Causa, R Cavazzana, M Cavedon, M Cecconello, S Ceccuzzi, R Cesario, CD Challis, IT Chapman, S Chapman, M Chernyshova, D Choi, C Cianfarani, G Ciraolo, J Citrin, F Clairet, I Classen, R Coelho, JW Coenen, L Colas, G Conway, Y Corre, S Costea, F Crisanti, N Cruz, G Cseh, A Czarnecka, O D’Arcangelo, M De Angeli, G De Masi, G De Temmerman, G De Tommasi, J Decker, RS Delogu, R Dendy, P Denner, C Di Troia, M Dimitrova, R D’Inca, V Dorić, D Douai, A Drenik, B Dudson, D Dunai, M Dunne, BP Duval, L Easy, S Elmore, B Erdös, B Esposito, E Fable, M Faitsch, A Fanni, N Fedorczak, F Felici, J Ferreira, O Février, O Ficker, S Fietz, L Figini, A Figueiredo, A Fil, G Fishpool, M Fitzgerald, M Fontana, O Ford, L Frassinetti, R Fridström, D Frigione, G Fuchert, C Fuchs, M Furno Palumbo, S Futatani, L Gabellieri, K Gałązka, J Galdon-Quiroga, S Galeani, D Gallart, A Gallo, C Galperti, Y Gao, S Garavaglia, J Garcia, A Garcia-Carrasco, J Garcia-Lopez, M Garcia-Munoz, J-L Gardarein, L Garzotti, J Gaspar, E Gauthier, P Geelen, B Geiger, P Ghendrih, F Ghezzi, L Giacomelli, L Giannone, E Giovannozzi, C Giroud, C Gleason González, M Gobbin, TP Goodman, G Gorini, M Gospodarczyk, G Granucci, M Gruber, A Gude, L Guimarais, R Guirlet, J Gunn, P Hacek, S Hacquin, S Hall, C Ham, T Happel, J Harrison, D Harting, V Hauer, E Havlickova, T Hellsten, W Helou, S Henderson, P Hennequin, M Heyn, B Hnat, M Hölzl, D Hogeweij, C Honoré, C Hopf, J Horáček, G Hornung, L Horváth, Z Huang, A Huber, J Igitkhanov, V Igochine, M Imrisek, P Innocente, C Ionita-Schrittwieser, H Isliker, I Ivanova-Stanik, AS Jacobsen, P Jacquet, M Jakubowski, A Jardin, F Jaulmes, F Jenko, T Jensen, O Jeppe Miki Busk, M Jessen, E Joffrin, O Jones, T Jonsson, A Kallenbach, N Kallinikos, S Kálvin, A Kappatou, J Karhunen, A Karpushov, S Kasilov, G Kasprowicz, A Kendl, W Kernbichler, D Kim, A Kirk, S Kjer, I Klimek, G Kocsis, D Kogut, M Komm, SB Korsholm, HR Koslowski, M Koubiti, J Kovacic, K Kovarik, N Krawczyk, J Krbec, K Krieger, A Krivska, R Kube, O Kudlacek, T Kurki-Suonio, B Labit, FM Laggner, L Laguardia, A Lahtinen, P Lalousis, P Lang, P Lauber, N Lazányi, A Lazaros, HB Le, A Lebschy, J Leddy, L Lefévre, M Lehnen, F Leipold, A Lessig, M Leyland, L Li, Y Liang, B Lipschultz, YQ Liu, T Loarer, A Loarte, T Loewenhoff, B Lomanowski, VP Loschiavo, T Lunt, I Lupelli, H Lux, A Lyssoivan, J Madsen, P Maget, C Maggi, R Maggiora, ML Magnussen, J Mailloux, B Maljaars, A Malygin, P Mantica, M Mantsinen, M Maraschek, B Marchand, N Marconato, C Marini, M Marinucci, T Markovic, D Marocco, L Marrelli, Y Martin, JR Martin Solis, A Martitsch, S Mastrostefano, M Mattei, G Matthews, M Mavridis, M-L Mayoral, D Mazon, P McCarthy, R McAdams, G McArdle, P McCarthy, K McClements, R McDermott, B McMillan, G Meisl, A Merle, O Meyer, D Milanesio, F Militello, IG Miron, K Mitosinkova, J Mlynar, A Mlynek, D Molina, P Molina, I Monakhov, J Morales, D Moreau, P Morel, J-M Moret, A Moro, D Moulton, HW Müller, F Nabais, E Nardon, V Naulin, A Nemes-Czopf, F Nespoli, R Neu, AH Nielsen, SK Nielsen, V Nikolaeva, S Nimb, M Nocente, R Nouailletas, S Nowak, M Oberkofler, M Oberparleiter, R Ochoukov, T Odstrčil, J Olsen, J Omotani, MG O’Mullane, F Orain, N Osterman, R Paccagnella, S Pamela, L Pangione, M Panjan, G Papp, R Papřok, V Parail, FI Parra, A Pau, G Pautasso, S-P Pehkonen, A Pereira, E Perelli Cippo, V Pericoli Ridolfini, M Peterka, P Petersson, V Petrzilka, P Piovesan, C Piron, A Pironti, F Pisano, T Pisokas, R Pitts, I Ploumistakis, V Plyusnin, G Pokol, D Poljak, P Pölöskei, Z Popovic, G Pór, L Porte, S Potzel, I Predebon, M Preynas, G Primc, G Pucella, ME Puiatti, T Pütterich, M Rack, G Ramogida, C Rapson, J Juul Rasmussen, J Rasmussen, GA Rattá, S Ratynskaia, G Ravera, D Réfy, M Reich, H Reimerdes, F Reimold, M Reinke, D Reiser, M Resnik, C Reux, D Ripamonti, D Rittich, G Riva, M Rodriguez-Ramos, V Rohde, J Rosato, F Ryter, S Saarelma, R Sabot, F Saint-Laurent, M Salewski, A Salmi, D Samaddar, L Sanchis-Sanchez, J Santos, O Sauter, R Scannell, M Scheffer, M Schneider, B Schneider, P Schneider, M Schneller, R Schrittwieser, M Schubert, J Schweinzer, J Seidl, M Sertoli, S Šesnić, A Shabbir, A Shalpegin, B Shanahan, S Sharapov, U Sheikh, G Sias, B Sieglin, C Silva, A Silva, M Silva Fuglister, J Simpson, A Snicker, C Sommariva, C Sozzi, S Spagnolo, G Spizzo, M Spolaore, T Stange, M Stejner Pedersen, I Stepanov, J Stober, P Strand, A Šušnjara, W Suttrop, T Szepesi, B Tál, T Tala, P Tamain, G Tardini, M Tardocchi, A Teplukhina, D Terranova, D Testa, C Theiler, A Thornton, P Tolias, L Tophøj, W Treutterer, GL Trevisan, M Tripsky, C Tsironis, C Tsui, O Tudisco, A Uccello, J Urban, M Valisa, P Vallejos, M Valovic, H Van den Brand, B Vanovac, S Varoutis, S Vartanian, J Vega, G Verdoolaege, K Verhaegh, L Vermare, N Vianello, J Vicente, E Viezzer, L Vignitchouk, WAJ Vijvers, F Villone, B Viola, L Vlahos, I Voitsekhovitch, P Vondráček, NMT Vu, D Wagner, N Walkden, N Wang, T Wauters, M Weiland, V Weinzettl, E Westerhof, M Wiesenberger, M Willensdorfer, M Wischmeier, I Wodniak, E Wolfrum, D Yadykin, R Zagórski, I Zammuto, P Zanca, R Zaplotnik, P Zestanakis, W Zhang, S Zoletnik, M Zuin

Ion-scale turbulence in MAST: anomalous transport, subcritical transitions, and comparison to BES measurements

Plasma Physics and Controlled Fusion Institute of Physics 59:11 (2017) 114003

Authors:

F van Wyk, EG Highcock, AR Field, CM Roach, Alexander Schekochihin, Felix I Parra, W Dorland

Abstract:

We investigate the effect of varying the ion temperature gradient (ITG) and toroidal equilibrium scale sheared flow on ion-scale turbulence in the outer core of MAST by means of local gyrokinetic simulations. We show that nonlinear simulations reproduce the experimental ion heat flux and that the experimentally measured values of the ITG and the flow shear lie close to the turbulence threshold. We demonstrate that the system is subcritical in the presence of flow shear, i.e., the system is formally stable to small perturbations, but transitions to a turbulent state given a large enough initial perturbation. We propose that the transition to subcritical turbulence occurs via an intermediate state dominated by low number of coherent long-lived structures, close to threshold, which increase in number as the system is taken away from the threshold into the more strongly turbulent regime, until they fill the domain and a more conventional turbulence emerges. We show that the properties of turbulence are effectively functions of the distance to threshold, as quantified by the ion heat flux. We make quantitative comparisons of correlation lengths, times, and amplitudes between our simulations and experimental measurements using the MAST BES diagnostic. We find reasonable agreement of the correlation properties, most notably of the correlation time, for which significant discrepancies were found in previous numerical studies of MAST turbulence.

Electromagnetic zonal flow residual responses

Journal of Plasma Physics Cambridge University Press 83:4 (2017) 1-38

Authors:

PJ Catto, FI Parra, I Pusztai

Abstract:

The collisionless axisymmetric zonal flow residual calculation for a tokamak plasma is generalized to include electromagnetic perturbations. We formulate and solve the complete initial value zonal flow problem by retaining the fully self-consistent axisymmetric spatial perturbations in the electric and magnetic fields. Simple expressions for the electrostatic, shear and compressional magnetic residual responses are derived that provide a fully electromagnetic test of the zonal flow residual in gyrokinetic codes. Unlike the electrostatic potential, the parallel vector potential and the parallel magnetic field perturbations need not relax to flux functions for all possible initial conditions.

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