Publications by Felix Parra Diaz


stella: An operator-split, implicit-explicit delta f-gyrokinetic code for general magnetic field configurations

JOURNAL OF COMPUTATIONAL PHYSICS 391 (2019) 365-380

M Barnes, FI Parra, M Landreman


Overview of recent TJ-II stellarator results

NUCLEAR FUSION 59 (2019) ARTN 112019

E Ascasibar, D Alba, D Alegre, A Alonso, J Alonso, F de Aragon, A Baciero, JM Barcala, E Blanco, J Botija, L Bueno, S Cabrera, E de la Cal, I Calvo, A Cappa, D Carralero, R Carrasco, B Carreras, F Castejon, R Castro, A de Castro, G Catalan, AA Chmyga, M Chamorro, AW Cooper, A Dinklage, L Eliseev, T Estrada, M Ezzat, F Fernandez-Marina, JM Fontdecaba, L Garcia, I Garcia-Cortes, R Garcia-Gomez, JM Garcia-Regana, A Gonzalez-Jerez, G Grenfell, J Guasp, J Hernandez-Sanchez, J Hernanz, C Hidalgo, E Hollmann, A Jimenez-Denche, P Khabanov, N Kharchev, I Kirpitchev, R Kleiber, AS Kozachek, L Krupnik, F Lapayese, M Liniers, B Liu, D Lopez-Bruna, A Lopez-Fraguas, B Lopez-Miranda, J Lopez-Razola, U Losada, E de la Luna, A Martin de Aguilera, F Martin-Diaz, M Martinez-Fuentes, G Martin-Gomez, AB Martin-Rojo, J Martinez-Fernandez, KJ McCarthy, F Medina, M Medrano, L Melon, AV Melnikov, P Mendez, R Merino, FJ Miguel, B van Milligen, A Molinero, B Momo, P Monreal, S Mulas, Y Narushima, M Navarro, M Ochando, S Ohshima, J Olivares, E Oyarzabal, JL de Pablos, L Pacios, N Panadero, F Parra, I Pastor, A de la Pena, A Pereira, JR Pinzon, AB Portas, E Poveda, JA Quintana, FJ Ramos, GA Ratta, M Redondo, E Rincon, L Rios, C Rodriguez-Fernandez, L Rodriguez-Rodrigo, B Rojo, A Ros, E Rosa, E Sanchez, J Sanchez, M Sanchez, E Sanchez-Sarabia, S Satake, JA Sebastian, R Sharma, C Silva, ER Solano, A Soleto, BJ Sun, FL Tabares, D Tafalla, H Takahashi, N Tamura, A Tolkachev, J Vega, G Velasco, JL Velasco, S Yamamoto, B Zurro, TJ-Team


Intrinsic rotation driven by turbulent acceleration

PLASMA PHYSICS AND CONTROLLED FUSION 61 (2019) ARTN 025003

M Barnes, FI Parra


stella: An operator-split, implicit–explicit δf-gyrokinetic code for general magnetic field configurations

Journal of Computational Physics Elsevier BV 391 (2019) 365-380

M Barnes, FI Parra, M Landreman


A scale-separated approach for studying coupled ion and electron scale turbulence

PLASMA PHYSICS AND CONTROLLED FUSION 61 (2019) ARTN 065025

MR Hardman, M Barnes, CM Roach, FI Parra


Overview of new MAST physics in anticipation of first results from MAST Upgrade

NUCLEAR FUSION 59 (2019) ARTN 112011

JR Harrison, RJ Akers, SY Allan, JS Allcock, JO Allen, L Appel, M Barnes, N Ben Ayedl, W Boeglin, C Bowman, J Bradley, P Browning, P Bryant, M Carr, M Cecconello, CD Challis, S Chapman, IT Chapman, GJ Colyer, S Conroy, NJ Conway, M Cox, G Cunningham, RO Dendy, W Dorland, BD Dudson, L Easy, SD Elmore, T Farley, X Feng, AR Field, A Fil, GM Fishpool, M Fitzgerald, K Flesch, MFJ Fox, H Frerichs, S Gadgil, D Gahle, L Garzotti, Y-C Ghim, S Gibson, KJ Gibson, S Hall, C Ham, N Heiberg, SS Henderson, E Highcock, B Hnat, J Howard, J Huang, SWA Irvine, AS Jacobsen, O Jones, I Katramados, D Keeling, A Kirk, I Klimek, L Kogan, J Leland, B Lipschultz, B Lloyd, J Lovell, B Madsen, O Marshall, R Martin, G McArdle, K McClements, B McMillan, A Meakins, HF Meyer, F Militello, J Milnes, S Mordijck, AW Morris, D Moulton, D Muir, K Mukhi, S Murphy-Sugrue, O Myatra, G Naylor, P Naylor, SL Newton, T O'Gorman, J Omotani, MG O'Mullane, S Orchard, SJP Pamela, L Pangione, F Parra, RV Perez, L Piron, M Price, ML Reinke, F Riva, CM Roach, D Robb, D Ryan, S Saarelma, M Salewski, S Scannell, AA Schekochihin, O Schmitz, S Sharapov, R Sharples, SA Silburn, SF Smith, A Sperduti, R Stephen, NT Thomas-Davies, AJ Thornton, M Turnyanskiy, M Valovic, F Van Wyk, RGL Vann, NR Walkden, I Waters, HR Wilson, MAST-U Team, EM Team


Large tangential electric fields in plasmas close to temperature screening

PLASMA PHYSICS AND CONTROLLED FUSION 60 (2018) ARTN 074004

JL Velasco, I Calvo, JM Garcia-Regana, FI Parra, S Satake, JA Alonso, LHD Team


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

VH Hall-Chen, FI Parra, JC Hillesheim


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

NUCLEAR FUSION 58 (2018) ARTN 026003

J Ball, FI Parra, M Landreman, M Barnes


Electrostatic potential variations on stellarator magnetic surfaces in low collisionality regimes

JOURNAL OF PLASMA PHYSICS 84 (2018) ARTN 905840407

I Calvo, J Luis Velasco, FI Parra, J Arturo Alonso, J Manuel Garcia-Regana


Stellarator impurity flux driven by electric fields tangent to magnetic surfaces

NUCLEAR FUSION 58 (2018) ARTN 124005

I Calvo, FI Parra, J Luis Velaso, J Arturo Alonso, JM Garcia-Regana


Solution to a collisionless shallow-angle magnetic presheath with kinetic ions

Plasma Physics and Controlled Fusion IOP Publishing (2018)

A Geraldini, FI Parra, F Militello

Using a kinetic model for the ions and adiabatic electrons, we solve a steady state, electron-repelling magnetic presheath in which a uniform magnetic field makes a small angle $\alpha \ll 1$ (in radians) with the wall. The presheath characteristic thickness is the typical ion gyroradius $\rho_{\text{i}}$. The Debye length $\lambda_{\text{D}}$ and the collisional mean free path of an ion $\lambda_{\text{mfp}}$ satisfy the ordering $\lambda_{\text{D}} \ll \rho_{\text{i}} \ll \alpha \lambda_{\text{mfp}}$, so a quasineutral and collisionless model is used. We assume that the electrostatic potential is a function only of distance from the wall, and it varies over the scale $\rho_{\text{i}}$. Using the expansion in $\alpha \ll 1$, we derive an analytical expression for the ion density that only depends on the ion distribution function at the entrance of the magnetic presheath and the electrostatic potential profile. Importantly, we have added the crucial contribution of the orbits in the region near the wall. By imposing the quasineutrality equation, we derive a condition that the ion distribution function must satisfy at the magnetic presheath entrance --- the kinetic equivalent of the Chodura condition. Using an ion distribution function at the entrance of the magnetic presheath that satisfies the kinetic Chodura condition, we find numerical solutions for the self-consistent electrostatic potential, ion density and flow across the magnetic presheath for several values of $\alpha$. Our numerical results also include the distribution of ion velocities at the Debye sheath entrance. We find that at small values of $\alpha$ there are substantially fewer ions travelling with a large normal component of the velocity into the wall.


Semianalytical calculation of the zonal-flow oscillation frequency in stellarators

PLASMA PHYSICS AND CONTROLLED FUSION 59 (2017) ARTN 065005

P Monreal, E Sanchez, I Calvo, A Bustos, FI Parra, A Mishchenko, A Koenies, R Kleiber


Overview of recent physics results from MAST

NUCLEAR FUSION 57 (2017) ARTN 102007

A Kirk, J Adamek, RJ Akers, S Allan, L Appel, FA Lucini, M Barnes, T Barrett, N Ben Ayed, W Boeglin, J Bradley, PK Browning, J Brunner, P Cahyna, S Cardnell, M Carr, F Casson, M Cecconello, C Challis, IT Chapman, S Chapman, J Chorley, S Conroy, N Conway, WA Cooper, M Cox, N Crocker, B Crowley, G Cunningham, A Danilov, D Darrow, R Dendy, D Dickinson, W Dorland, B Dudson, D Dunai, L Easy, S Elmore, M Evans, T Farley, N Fedorczak, A Field, G Fishpool, I Fitzgerald, M Fox, S Freethy, L Garzotti, YC Ghim, K Gi, K Gibson, M Gorelenkova, W Gracias, C Gurl, W Guttenfelder, C Ham, J Harrison, D Harting, E Havlickova, N Hawkes, T Hender, S Henderson, E Highcock, J Hillesheim, B Hnat, J Horacek, J Howard, D Howell, B Huang, K Imada, M Inomoto, R Imazawa, O Jones, K Kadowaki, S Kaye, D Keeling, I Klimek, M Kocan, L Kogan, M Komm, W Lai, J Leddy, H Leggate, J Hollocombe, B Lipschultz, S Lisgo, YQ Liu, B Lloyd, B Lomanowski, V Lukin, I Lupelli, G Maddison, J Madsen, J Mailloux, R Martin, G McArdle, K McClements, B McMillan, A Meakins, H Meyer, C Michael, F Militello, J Milnes, AW Morris, G Motojima, D Muir, G Naylor, A Nielsen, M O'Brien, T O'Gorman, M O'Mullane, J Olsen, J Omotani, Y Ono, S Pamela, L Pangione, F Parra, A Patel, W Peebles, R Perez, S Pinches, L Piron, M Price, M Reinke, P Ricci, F Riva, C Roach, M Romanelli, D Ryan, S Saarelma, A Saveliev, R Scannell, A Schekochihin, S Sharapov, R Sharples, V Shevchenko, K Shinohara, S Silburn, J Simpson, A Stanier, J Storrs, H Summers, Y Takase, P Tamain, H Tanabe, H Tanaka, K Tani, D Taylor, D Thomas, N Thomas-Davies, A Thornton, M Turnyanskiy, M Valovic, R Vann, F Van Wyk, N Walkden, T Watanabe, H Wilson, M Wischmeier, T Yamada, J Young, S Zoletnik, MAST Team, EM Team


The effect of tangential drifts on neoclassical transport in stellarators close to omnigeneity

PLASMA PHYSICS AND CONTROLLED FUSION 59 (2017) ARTN 055014

I Calvo, FI Parra, J Luis Velasco, JA Alonso


Electromagnetic zonal flow residual responses

JOURNAL OF PLASMA PHYSICS 83 (2017) ARTN 905830402

PJ Catto, FI Parra, I Pusztai


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

PLASMA PHYSICS AND CONTROLLED FUSION 59 (2017) ARTN 114003

F van Wyk, EG Highcock, AR Field, CM Roach, AA Schekochihin, FI Parra, W Dorland


Observation of Oscillatory Radial Electric Field Relaxation in a Helical Plasma.

Physical review letters 118 (2017) 185002-

JA Alonso, E Sánchez, I Calvo, JL Velasco, KJ McCarthy, A Chmyga, LG Eliseev, T Estrada, R Kleiber, LI Krupnik, AV Melnikov, P Monreal, FI Parra, S Perfilov, AI Zhezhera, TJ-II Team

Measurements of the relaxation of a zonal electrostatic potential perturbation in a nonaxisymmetric magnetically confined plasma are presented. A sudden perturbation of the plasma equilibrium is induced by the injection of a cryogenic hydrogen pellet in the TJ-II stellarator, which is observed to be followed by a damped oscillation in the electrostatic potential. The waveform of the relaxation is consistent with theoretical calculations of zonal potential relaxation in a nonaxisymmetric magnetic geometry. The turbulent transport properties of a magnetic confinement configuration are expected to depend on the features of the collisionless damping of zonal flows, of which the present Letter is the first direct observation.


Overview of progress in European medium sized tokamaks towards an integrated plasma-edge/wall solution

NUCLEAR FUSION 57 (2017) ARTN 102014

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 Andrebe, 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 Bilkova, W Bin, G Birkenmeier, JPS Bizarro, P Blanchard, T Blanken, M Bluteau, V Bobkov, O Bogar, P Boehm, T Bolzonella, L Boncagni, A Botrugno, C Bottereau, F Bouquey, C Bourdelle, S Bremond, S Brezinsek, D Brida, F Brochard, J Buchanan, H Bufferand, P Buratti, P Cahyna, G Calabro, Y Camenen, R Caniello, B Cannas, A Canton, A Cardinali, D Carnevale, M Carr, D Carralero, P Carvalho, L Casali, C Castaldo, F Castejon, 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 Doric, D Douai, A Drenik, B Dudson, D Dunai, M Dunne, BP Duval, L Easy, S Elmore, B Erdos, B Esposito, E Fable, M Faitsch, A Fanni, N Fedorczak, F Felici, J Ferreira, O Fevrier, O Ficker, S Fietz, L Figini, A Figueiredo, A Fil, G Fishpool, M Fitzgerald, M Fontana, O Ford, L Frassinetti, R Fridstr, D Frigione, G Fuchert, C Fuchs, MF Palumbo, S Futatani, L Gabellieri, K Galazka, 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 Gonzalez, 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 Holzl, D Hogeweij, C Honore, C Hopf, J Horacek, G Hornung, L Horvath, 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, OJM Busk, M Jessen, E Joffrin, O Jones, T Jonsson, A Kallenbach, N Kallinikos, S Kalvin, 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 Lazanyi, A Lazaros, HB Le, A Lebschy, J Leddy, L Lefevre, 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, JRM 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 Mueller, 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 Odstrcil, J Olsen, J Omotani, MG O'Mullane, F Orain, N Osterman, R Paccagnella, S Pamela, L Pangione, M Panjan, G Papp, R Paprok, V Parail, I Parra, A Pau, G Pautasso, S-P Pehkonen, A Pereira, EP Cippo, VP 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 Poloskei, Z Popovic, G Por, L Porte, S Potzel, I Predebon, M Preynas, G Primc, G Pucella, ME Puiatti, T Putterich, M Rack, G Ramogida, C Rapson, JJ Rasmussen, J Rasmussen, GA Ratta, S Ratynskaia, G Ravera, D Refy, 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 Sesnic, A Shabbir, A Shalpegin, B Shanahan, S Sharapov, U Sheikh, G Sias, B Sieglin, C Silva, A Silva, MS Fuglister, J Simpson, A Snicker, C Sommariva, C Sozzi, S Spagnolo, G Spizzo, M Spolaore, T Stange, MS Pedersen, I Stepanov, J Stober, P Strand, A Susnjara, W Suttrop, T Szepesi, B Tal, T Tala, P Tamain, G Tardini, M Tardocchi, A Teplukhina, D Terranova, D Testa, C Theiler, A Thornton, P Tolias, L Tophoj, 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 Vondracek, 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 Zagorski, I Zammuto, P Zanca, R Zaplotnik, P Zestanakis, W Zhang, S Zoletnik, M Zuin, ASDEXU Team, MAST Team, TCV Team


Stellarator bootstrap current and plasma flow velocity at low collisionality

JOURNAL OF PLASMA PHYSICS 83 (2017) ARTN 905830206

P Helander, FI Parra, SL Newton

Pages