Preparing for first diverted plasma operation in the ST40 high-field spherical tokamak

47th EPS Conference on Plasma Physics, EPS 2021 2021-June (2021) 681-684

Authors:

M Romanelli, S McNamara, P Buxton, O Asunta, J Varje, J Wood, C Marsden, J Bland, V Nemytov, P Thomas, M Gryaznevich, M Sertoli, B Vincent, S Sridhar, A Dnestrovsky, S Medvedev, V Drozdov, S Janhunen, J Sinha, T Bogaarts, G Rubino, P Innocenti, G Calabro, M Scarpari, P Fanelli, F Giorgetti, R Lombroni, S Kaye, A Diallo, W Guttenfelder, M Barnes, Y Zhang

Abstract:

The ST40 tokamak [1], built and operated by Tokamak Energy, has recently been upgraded with upper and lower divertors to enable double null diverted operations with up to 1MA plasma current and 2MW neutral beam heating. ST40 is a high field spherical tokamak (ST), BT=3T at R0=0.4m with a goal to extend the high field spherical tokamak physics basis. Crucially, transport and confinement in high field, high temperature STs will be explored in support to the design of next step STs [2]. Extensive modelling activities have been undertaken to prepare for the exploitation of ST40. A range of plasma equilibrium in double-null configuration have been designed along with detailed scenario modelling, including 1.5D transport simulations and 2D SOL modelling. Gyrokinetic analysis has been performed to assess the level of expected turbulent transport. Building upon the NSTX pedestal database the pedestal width and height in the high performance ST40 scenarios have been predicted. MHD stability analysis and beta limit have been assessed. ST40 will be initially operated in hydrogen with up to 1.5 MW NBI (0.8MW at 55kV and 0.7MW at 25kV). The heating systems will be upgraded in view of the follow up campaign in deuterium, with 2MW, 55kV NBI and around 1.6MW 105/140GHz ECRH. Careful analysis of the power deposited in the divertor during high performance operation has also been carried out.

Dynamical Formation of Merging Stellar-Mass Binary Black Holes

Chapter in Handbook of Gravitational Wave Astronomy, Springer Nature (2021) 1-44

Thermal equilibrium of an ideal gas in a free-floating box

(2020)

Authors:

Scott Tremaine, Bence Kocsis, Abraham Loeb

Observation of a sudden cessation of a very-high-energy gamma-ray flare in PKS 1510-089 with H.E.S.S. and MAGIC in May 2016

ArXiv 2012.10254 (2020)

Authors:

HESS Collaboration, H Abdalla, R Adam, F Aharonian, F Ait Benkhali, EO Angüner, C Arcaro, C Arm, T Armstrong, H Ashkar, M Backes, V Baghmanyan, V Barbosa Martins, A Barnacka, M Barnard, Y Becherini, D Berge, K Bernlöhr, B Bi, M Böttcher, C Boisson, J Bolmont, S Bonnefoy, M de Bony de Lavergne, J Bregeon, M Breuhaus, F Brun, P Brun, M Bryan, M Büchele, T Bulik, T Bylund, S Caroff, A Carosi, S Casanova, T Ch, S Ch, A Chen, G Cotter, M Curyło, J Damascene Mbarubucyeye, ID Davids, J Davies, C Deil, J Devin, P deWilt, L Dirson, A Djannati-Ataï, A Dmytriiev, A Donath, V Doroshenko, J Dyks, K Egberts, F Eichhorn, S Einecke, G Emery, J-P Ernenwein, K Feijen, S Fegan, A Fiasson, G Fichet de Clairfontaine, M Filipovic, G Fontaine, S Funk, M Füßling, S Gabici, YA Gallant, G Giavitto, L Giunti, D Glawion, JF Glicenstein, D Gottschall, M-H Grondin, J Hahn, M Haupt, G Hermann, JA Hinton, W Hofmann, C Hoischen, TL Holch, M Holler, M Hörbe, D Horns, D Huber, M Jamrozy, D Jankowsky, F Jankowsky, A Jardin-Blicq, V Joshi, I Jung-Richardt, MA Kastendieck, K Katarzyński, U Katz, D Khangulyan, B Khélifi, S Klepser, W Kluźniak, Nu Komin, R Konno, K Kosack, D Kostunin, M Kreter, G Lamanna, A Lemière, M Lemoine-Goumard, J-P Lenain, C Levy, T Lohse, I Lypova, J Mackey, J Majumdar, D Malyshev, D Malyshev, V Mar, P Marchegiani, A Marcowith, A Mares, G Martí-Devesa, R Marx, G Maurin, PJ Meintjes, M Meyer, AMW Mitchell, R Moderski, M Mohamed, L Mohrmann, A Montanari, C Moore, P Morris, E Moulin, J Muller, T Murach, K Nakashima, A Nayerhoda, M de Naurois, H Ndiyavala, F Niederwanger, J Niemiec, L Oakes, P O'Brien, H Odaka, S Ohm, L Olivera-Nieto, E de Ona Wilhelmi, M Ostrowski, M Panter, S Panny, RD Parsons, G Peron, B Peyaud, Q Piel, S Pita, V Poireau, A Priyana Noel, DA Prokhorov, H Prokoph, G Pühlhofer, M Punch, A Quirrenbach, S Raab, R Rauth, P Reichherzer, A Reimer, O Reimer, Q Remy, M Renaud, F Rieger, L Rinchiuso, C Romoli, G Rowell, B Rudak, E Ruiz-Velasco, V Sahakian, S Sailer, DA Sanchez, A Santangelo, M Sasaki, M Scalici, F Schüssler, HM Schutte, U Schwanke, S Schwemmer, M Seglar-Arroyo, M Senniappan, AS Seyffert, N Shafi, K Shiningayamwe, R Simoni, A Sinha, H Sol, A Specovius, S Spencer, M Spir-Jacob, Ł Stawarz, L Sun, R Steenkamp, C Stegmann, S Steinmassl, C Steppa, T Takahashi, T Tavernier, AM Taylor, R Terrier, D Tiziani, M Tluczykont, L Tomankova, C Trichard, M Tsirou, R Tuffs, Y Uchiyama, DJ van der Walt, C van Eldik, C van Rensburg, B van Soelen, G Vasileiadis, J Veh, C Venter, P Vincent, J Vink, HJ Völk, T Vuillaume, Z Wadiasingh, SJ Wagner, J Watson, F Werner, R White, A Wierzcholska, Yu Wun Wong, A Yusafzai, M Zacharias, R Zanin, D Zargaryan, AA Zdziarski, A Zech, SJ Zhu, J Zorn, S Zouari, N Żywucka, MAGIC Collaboration, VA Acciari, S Ansoldi, LA Antonelli, A Arbet Engels, K Asano, D Baack, A Babić, A Baquero, U Barres de Almeida, JA Barrio, J Becerra González, W Bednarek, L Bellizzi, E Bernardini, A Berti, J Besenrieder, W Bhattacharyya, C Bigongiari, A Bil, O Blanch, G Bonnoli, Ž Bošnjak, G Busetto, R Carosi, G Ceribella, M Cerruti, Y Chai, A Chilingarian, S Cikota, SM Colak, U Colin, E Colombo, JL Contreras, J Cortina, S Covino, G D'Amico, V D'Elia, P Da Vela, F Dazzi, A De Angelis, B De Lotto, M Delfino, J Delgado, D Depaoli, F Di Pierro, L Di Venere, E Do Souto Espi neira, D Dominis Prester, A Donini, D Dorner, M Doro, D Elsaesser, V Fallah Ramazani, A Fattorini, G Ferrara, L Foffano, MV Fonseca, L Font, C Fruck, S Fukami, RJ García López, M Garczarczyk, S Gasparyan, M Gaug, N Giglietto, F Giordano, P Gliwny, N Godinović, D Green, D Hadasch, A Hahn, L Heckmann, J Herrera, J Hoang, D Hrupec, M Hütten, T Inada, S Inoue, K Ishio, Y Iwamura, L Jouvin, Y Kajiwara, M Karjalainen, D Kerszberg, Y Kobayashi, H Kubo, J Kushida, A Lamastra, D Lelas, F Leone, E Lindfors, S Lombardi, F Longo, M López, R López-Coto, A López-Oramas, S Loporchio, B Machado de Oliveira Fraga, C Maggio, P Majumdar, M Makariev, M Mallamaci, G Maneva, M Manganaro, K Mannheim, L Maraschi, M Mariotti, M Martínez, D Mazin, S Mender, S Mićanović, D Miceli, T Miener, M Minev, JM Mir, R Mirzoyan, E Molina, A Moralejo, D Morcuende, V Moreno, E Moretti, P Munar-Adrover, V Neustroev, C Nigro, K Nilsson, D Ninci, K Nishijima, K Noda, S Nozaki, Y Ohtani, T Oka, J Otero-Santos, M Palatiello, D Paneque, R Paoletti, JM Paredes, L Pavletić, P Pe nil, C Perennes, M Persic, PG Prada Moroni, E Pr, C Priyadarshi, I Puljak, W Rhode, M Ribó, J Rico, C Righi, A Rugliancich, L Saha, N Sahakyan, T Saito, S Sakurai, K Satalecka, B Schleicher, K Schmidt, T Schweizer, J Sitarek, I Šnidarić, D Sobczynska, A Spolon, A Stamerra, D Strom, M Strzys, Y Suda, T Surić, M Takahashi, F Tavecchio, P Temnikov, T Terzić, M Teshima, N Torres-Albà, L Tosti, S Truzzi, J van Scherpenberg, G Vanzo, M Vazquez Acosta, S Ventura, V Verguilov, CF Vigorito, V Vitale, I Vovk, M Will, D Zarić, SG Jorstad, AP Marscher, B Boccardi, C Casadio, J Hodgson, J-Y Kim, TP Krichbaum, A Lähteenmäki, M Tornikoski, E Traianou, ZR Weaver

Ion versus electron heating in compressively driven astrophysical gyrokinetic turbulence

Physical Review X American Physical Society 10:4 (2020) 41050

Authors:

Y Kawazura, Aa Schekochihin, M Barnes, Jm TenBarge, Y Tong, Kg Klein, W Dorland

Abstract:

The partition of irreversible heating between ions and electrons in compressively driven (but subsonic) collisionless turbulence is investigated by means of nonlinear hybrid gyrokinetic simulations. We derive a prescription for the ion-to-electron heating ratio Qi/Qe as a function of the compressive-to-Alfvénic driving power ratio Pcompr/PAW, of the ratio of ion thermal pressure to magnetic pressure βi, and of the ratio of ion-to-electron background temperatures Ti/Te. It is shown that Qi/Qe is an increasing function of Pcompr/PAW. When the compressive driving is sufficiently large, Qi/Qe approaches ≃Pcompr/PAW. This indicates that, in turbulence with large compressive fluctuations, the partition of heating is decided at the injection scales, rather than at kinetic scales. Analysis of phase-space spectra shows that the energy transfer from inertial-range compressive fluctuations to sub-Larmor-scale kinetic Alfvén waves is absent for both low and high βi, meaning that the compressive driving is directly connected to the ion-entropy fluctuations, which are converted into ion thermal energy. This result suggests that preferential electron heating is a very special case requiring low βi and no, or weak, compressive driving. Our heating prescription has wide-ranging applications, including to the solar wind and to hot accretion disks such as M87 and Sgr A*.