TY - JOUR
T1 - Runaway electron beam control
AU - Saint Petersburg IAEA - FEC2014 - G. Pucella
AU - The ASDEX Upgrade, MAST and TCV Teams
AU - JET Contributors
AU - the FTU results G Pucella
AU - Bombarda, F.
AU - Calacci, L.
AU - Cordella, F.
AU - Ferrò, G.
AU - Gabrielli, A.
AU - Havranek, A.
AU - Lier, A.
AU - Macusova, E.
AU - Martinelli, F.
AU - Passeri, M.
AU - Possieri, C.
AU - Tilia, B.
AU - Bagnato, F.
AU - Angelini, B.
AU - Apicella, M. L.
AU - Artaserse, G.
AU - Barbato, E.
AU - Bertocchi, A.
AU - Briguglio, S.
AU - Bruschi, A.
AU - Centioli, C.
AU - Cirant, S.
AU - de Angelis, R.
AU - Farina, D.
AU - Fogaccia, G.
AU - Fusco, V.
AU - Grossetti, G.
AU - Grosso, G.
AU - Iannone, F.
AU - Kroegler, H.
AU - Lontano, M.
AU - Maddaluno, G.
AU - Mazzitelli, G.
AU - Milovanov, A.
AU - Krivska, A.
AU - Lyssoivan, A.
AU - Stepanov, I.
AU - Verdoolaege, G.
AU - Wauters, T.
AU - Crombé, K.
AU - Dumortier, P.
AU - Durodié, F.
AU - Jachmich, S.
AU - Kazakov, Y.
AU - Lerche, E.
AU - Messiaen, A.
AU - Moradi, S.
AU - Ongena, J.
AU - Ragona, R.
AU - van Eester, D.
N1 - Publisher Copyright:
© 2018 IOP Publishing Ltd.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Post-disruption runaway electron (RE) beams in tokamaks with large current can cause deep melting of the vessel and are one of the major concerns for ITER operations. Consequently, a considerable effort is provided by the scientific community in order to test RE mitigation strategies. We present an overview of the results obtained at FTU and TCV controlling the current and position of RE beams to improve safety and repeatability of mitigation studies such as massive gas (MGI) and shattered pellet injections (SPI). We show that the proposed RE beam controller (REB-C) implemented at FTU and TCV is effective and that current reduction of the beam can be performed via the central solenoid reducing the energy of REs, providing an alternative/parallel mitigation strategy to MGI/SPI. Experimental results show that, meanwhile deuterium pellets injected on a fully formed RE beam are ablated but do not improve RE energy dissipation rate, heavy metals injected by a laser blow off system on low-density flat-top discharges with a high level of RE seeding seem to induce disruptions expelling REs. Instabilities during the RE beam plateau phase have shown to enhance losses of REs, expelled from the beam core. Then, with the aim of triggering instabilities to increase RE losses, an oscillating loop voltage has been tested on RE beam plateau phase at TCV revealing, for the first time, what seems to be a full conversion from runaway to ohmic current. We finally report progresses in the design of control strategies at JET in view of the incoming SPI mitigation experiments.
AB - Post-disruption runaway electron (RE) beams in tokamaks with large current can cause deep melting of the vessel and are one of the major concerns for ITER operations. Consequently, a considerable effort is provided by the scientific community in order to test RE mitigation strategies. We present an overview of the results obtained at FTU and TCV controlling the current and position of RE beams to improve safety and repeatability of mitigation studies such as massive gas (MGI) and shattered pellet injections (SPI). We show that the proposed RE beam controller (REB-C) implemented at FTU and TCV is effective and that current reduction of the beam can be performed via the central solenoid reducing the energy of REs, providing an alternative/parallel mitigation strategy to MGI/SPI. Experimental results show that, meanwhile deuterium pellets injected on a fully formed RE beam are ablated but do not improve RE energy dissipation rate, heavy metals injected by a laser blow off system on low-density flat-top discharges with a high level of RE seeding seem to induce disruptions expelling REs. Instabilities during the RE beam plateau phase have shown to enhance losses of REs, expelled from the beam core. Then, with the aim of triggering instabilities to increase RE losses, an oscillating loop voltage has been tested on RE beam plateau phase at TCV revealing, for the first time, what seems to be a full conversion from runaway to ohmic current. We finally report progresses in the design of control strategies at JET in view of the incoming SPI mitigation experiments.
KW - magnetic confinement
KW - plasma control system
KW - runaways
UR - http://www.scopus.com/inward/record.url?scp=85057828309&partnerID=8YFLogxK
U2 - 10.1088/1361-6587/aaef53
DO - 10.1088/1361-6587/aaef53
M3 - Article
AN - SCOPUS:85057828309
SN - 0741-3335
VL - 61
JO - Plasma Physics and Controlled Fusion
JF - Plasma Physics and Controlled Fusion
IS - 1
M1 - 014036
ER -