On the minimum transport required to passively suppress runaway electrons in SPARC disruptions
Journal article, 2023

In Izzo et al (2022 Nucl. Fusion 62 096029), state-of-the-art modeling of thermal and current quench (CQ) magnetohydrodynamics (MHD) coupled with a self-consistent evolution of runaway electron (RE) generation and transport showed that a non-axisymmetric (n = 1) in-vessel coil could passively prevent RE beam formation during disruptions in SPARC, a compact high-field tokamak projected to achieve a fusion gain Q > 2 in DT plasmas. However, such suppression requires finite transport of REs within magnetic islands and re-healed flux surfaces; conservatively assuming zero transport in these regions leads to an upper bound of RE current ∼ 1 M A compared to ∼ 8.7 M A of pre-disruption plasma current. Further investigation finds that core-localized electrons, within r / a < 0.3 and with kinetic energies ∼ 0.2 - 15 M e V , contribute most to the RE plateau formation. Yet only a relatively small amount of transport, i.e. a diffusion coefficient ∼ 18 m 2 s − 1 , is needed in the core to fully mitigate these REs. Properly accounting for (a) the CQ electric field’s effect on RE transport in islands and (b) the contribution of significant RE currents to disruption MHD may help achieve this.



runaway electrons

passive mitigation



R. A. Tinguely

Massachusetts Institute of Technology (MIT)

Istvan Pusztai

Chalmers, Physics, Subatomic, High Energy and Plasma Physics

V. Izzo

Fiat Lux

K. Sarkimaki

Max Planck Society

Tünde-Maria Fülöp

Chalmers, Physics, Subatomic, High Energy and Plasma Physics

D. T. Garnier

Massachusetts Institute of Technology (MIT)

R. S. Granetz

Massachusetts Institute of Technology (MIT)

M. Hoppe

Swiss Federal Institute of Technology in Lausanne (EPFL)

C. Paz-Soldan

Columbia University

Andréas Sundström

Chalmers, Physics, Subatomic, High Energy and Plasma Physics

R. Sweeney

Massachusetts Institute of Technology (MIT)

Plasma Physics and Controlled Fusion

0741-3335 (ISSN) 1361-6587 (eISSN)

Vol. 65 3 034002

Runaway electrons in fusion plasmas

Swedish Research Council (VR) (2018-03911), 2018-12-01 -- 2021-12-31.

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Other Physics Topics

Fusion, Plasma and Space Physics

Condensed Matter Physics



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