Expulsion of runaway electrons using ECRH in the TCV tokamak

Fuente: arXiv
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Main Authors: Decker, J., Hoppe, M., Sheikh, U., Duval, B. P., Papp, G., Simons, L., Wijkamp, T., Cazabonne, J., Coda, S., Devlaminck, E., Ficker, O., Hellinga, R., Kumar, U., Savoye-Peysson, Y., Porte, L., Reux, C., Sommariva, C., Biwolé, A. Tema, Vincent, B., Votta, L., Team, the TCV, Team, the EUROfusion Tokamak Exploitation
Format: Preprint
Published: 2024
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author Decker, J.
Hoppe, M.
Sheikh, U.
Duval, B. P.
Papp, G.
Simons, L.
Wijkamp, T.
Cazabonne, J.
Coda, S.
Devlaminck, E.
Ficker, O.
Hellinga, R.
Kumar, U.
Savoye-Peysson, Y.
Porte, L.
Reux, C.
Sommariva, C.
Biwolé, A. Tema
Vincent, B.
Votta, L.
Team, the TCV
Team, the EUROfusion Tokamak Exploitation
author_facet Decker, J.
Hoppe, M.
Sheikh, U.
Duval, B. P.
Papp, G.
Simons, L.
Wijkamp, T.
Cazabonne, J.
Coda, S.
Devlaminck, E.
Ficker, O.
Hellinga, R.
Kumar, U.
Savoye-Peysson, Y.
Porte, L.
Reux, C.
Sommariva, C.
Biwolé, A. Tema
Vincent, B.
Votta, L.
Team, the TCV
Team, the EUROfusion Tokamak Exploitation
contents Runaway electrons (REs) are a concern for tokamak fusion reactors from discharge startup to termination. A sudden localized loss of a multi-megaampere RE beam can inflict severe damage to the first wall. Should a disruption occur, the existence of a RE seed may play a significant role in the formation of a RE beam and the magnitude of its current. The application of central electron cyclotron resonance heating (ECRH) in the Tokamak à Configuration Variable (TCV) reduces an existing RE seed population by up to three orders of magnitude within only a few hundred milliseconds. Applying ECRH before a disruption can also prevent the formation of a post-disruption RE beam in TCV where it would otherwise be expected. The RE expulsion rate and consequent RE current reduction are found to increase with applied ECRH power. Whereas central ECRH is effective in expelling REs, off-axis ECRH has a comparatively limited effect. A simple 0-D model for the evolution of the RE population is presented that explains the effective ECRH-induced RE expulsion results from the combined effects of increased electron temperature and enhanced RE transport.
format Preprint
id arxiv_https___arxiv_org_abs_2404_09900
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Expulsion of runaway electrons using ECRH in the TCV tokamak
Decker, J.
Hoppe, M.
Sheikh, U.
Duval, B. P.
Papp, G.
Simons, L.
Wijkamp, T.
Cazabonne, J.
Coda, S.
Devlaminck, E.
Ficker, O.
Hellinga, R.
Kumar, U.
Savoye-Peysson, Y.
Porte, L.
Reux, C.
Sommariva, C.
Biwolé, A. Tema
Vincent, B.
Votta, L.
Team, the TCV
Team, the EUROfusion Tokamak Exploitation
Plasma Physics
Runaway electrons (REs) are a concern for tokamak fusion reactors from discharge startup to termination. A sudden localized loss of a multi-megaampere RE beam can inflict severe damage to the first wall. Should a disruption occur, the existence of a RE seed may play a significant role in the formation of a RE beam and the magnitude of its current. The application of central electron cyclotron resonance heating (ECRH) in the Tokamak à Configuration Variable (TCV) reduces an existing RE seed population by up to three orders of magnitude within only a few hundred milliseconds. Applying ECRH before a disruption can also prevent the formation of a post-disruption RE beam in TCV where it would otherwise be expected. The RE expulsion rate and consequent RE current reduction are found to increase with applied ECRH power. Whereas central ECRH is effective in expelling REs, off-axis ECRH has a comparatively limited effect. A simple 0-D model for the evolution of the RE population is presented that explains the effective ECRH-induced RE expulsion results from the combined effects of increased electron temperature and enhanced RE transport.
title Expulsion of runaway electrons using ECRH in the TCV tokamak
topic Plasma Physics
url https://arxiv.org/abs/2404.09900