Assessment of runaway electron beam termination and impact in ITER

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openAccess

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Journal Title

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Volume Title

A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2024-07

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Mcode

Degree programme

Language

en

Pages

14

Series

Nuclear Fusion, Volume 64, issue 7, pp. 1-14

Abstract

The vertical motion and shrinking of the cold plasma column after a tokamak disruption leads to a natural decrease in the edge safety factor when most of the current is carried by runaway electrons (REs). Reaching a low edge safety factor can potentially cause a strong plasma instability. We present magnetohydrodynamic simulations of the termination of a post-disruption plateau-phase RE beam in ITER when the edge safety factor falls close to two. Growth of instabilities is observed to result in stochastization of the magnetic field and a prompt loss of REs. As RE impact must be mitigated in ITER, the effect of parameters that influence the final termination have been assessed. Higher background plasma resistivity is seen to cause larger mode magnitudes and stronger stochastization, leading to less remnant REs after the termination event. Lower ion-densities also project a qualitatively similar behavior although weaker in effect. Using computations from a wall collision model, the ensuing load distribution on the first-wall is also presented.

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Publisher Copyright: © 2024 The Author(s). Published by IOP Publishing Ltd on behalf of the IAEA. All rights reserved.

Keywords

benign termination, disruption, ITER, MHD, runaway electrons, stochastic fields, tokamak

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Citation

Bandaru, V, Hoelzl, M, Bergström, H, Artola, F J, Särkimäki, K, Lehnen, M & the JOREK Team 2024, ' Assessment of runaway electron beam termination and impact in ITER ', Nuclear Fusion, vol. 64, no. 7, 076053, pp. 1-14 . https://doi.org/10.1088/1741-4326/ad50ea