PreprintarXiv licencearXiv
Mechanism of Ionization Avalanche in Tokamak Microwave Gas Breakdown
Abstract
Microwave breakdown driven by electron cyclotron (EC) waves provides a non-inductive route to plasma initiation in reactor-scale tokamaks. We introduce a three-dimensional Monte Carlo simulation that, for the first time, self-consistently treats nonlinear wave-particle interactions, atomic collisions, and guiding-center transport. The Monte Carlo simulation unveils the key role of parallel Brownian motion in the ionization avalanche mechanism. The predicted breakdown boundary is validated against KSTAR experiments. This work concludes that microwave gas breakdown will be successful under ITER-relevant conditions at a D2 prefill pressure near 2 mPa with 1 MW of injected EC power.
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BibTeX
@misc{gwak2026mechanism,
title = {{Mechanism of Ionization Avalanche in Tokamak Microwave Gas Breakdown}},
author = {Jinwoo Gwak and Yeongsun Lee and Jeongwon Lee and Won Ik Jeong and Hyun-Tae Kim and Yong-Seok Hwang and Min-Gu Yoo and Yong-Su Na},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.21429},
eprint = {2609.21429},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.21429},
}
RIS
TY - UNPB
TI - Mechanism of Ionization Avalanche in Tokamak Microwave Gas Breakdown
AU - Jinwoo Gwak
AU - Yeongsun Lee
AU - Jeongwon Lee
AU - Won Ik Jeong
AU - Hyun-Tae Kim
AU - Yong-Seok Hwang
AU - Min-Gu Yoo
AU - Yong-Su Na
PY - 2026
DA - 2026/09/18
PB - arXiv
DO - 10.48550/arxiv.2609.21429
UR - https://arxiv.org/abs/2609.21429
AB - Microwave breakdown driven by electron cyclotron (EC) waves provides a non-inductive route to plasma initiation in reactor-scale tokamaks. We introduce a three-dimensional Monte Carlo simulation that, for the first time, self-consistently treats nonlinear wave-particle interactions, atomic collisions, and guiding-center transport. The Monte Carlo simulation unveils the key role of parallel Brownian motion in the ionization avalanche mechanism. The predicted breakdown boundary is validated against KSTAR experiments. This work concludes that microwave gas breakdown will be successful under ITER-relevant conditions at a D_2 prefill pressure near 2 mPa with 1 MW of injected EC power.
ER -