Simulation of runaway electron generation during plasma shutdown by impurity injection in ITER
Artikel i vetenskaplig tidskrift, 2011

Disruptions in a large tokamak can cause serious damage to the device and should be avoided or mitigated. Massive gas or killer pellet injection are possible ways to obtain a controlled fast plasma shutdown before a natural disruption occurs. In this work, plasma shutdown scenarios with different types of impurities are studied for an ITER-like plasma. Plasma cooling, runaway generation and the associated electric field diffusion are calculated with a 1D-code taking the Dreicer, hot-tail and avalanche runaway generation processes into account. Thin, radially localized sheets with high temperature can be created after the thermal quench, and the Dreicer and avalanche processes produce a high runaway current inside these sheets. At high impurity concentration the Dreicer process is suppressed but hot-tail runaways are created. Favorable thermal and current quench times can be achieved with a mixture of deuterium and neon or argon. However, to prevent the avalanche process from creating a significant runaway current fraction, it is found to be necessary to include runaway losses in the model.

Författare

Tamás Fehér

Chalmers, Teknisk fysik, Nukleär teknik

Tünde Fülöp

Chalmers, Teknisk fysik, Nukleär teknik

Kinga Gál

Plasma Physics and Controlled Fusion

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

Vol. 53 035014-

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Energi

Fundament

Grundläggande vetenskaper

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Fusion, plasma och rymdfysik