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Title: Relation of the runaway avalanche threshold to momentum space topology

Abstract

Here, the underlying physics responsible for the formation of an avalanche instability due to the generation of secondary electrons is studied. A careful examination of the momentum space topology of the runaway electron population is carried out with an eye toward identifying how qualitative changes in the momentum space of the runaway electrons is correlated with the avalanche threshold. It is found that the avalanche threshold is tied to the merger of an O and X point in the momentum space of the primary runaway electron population. Such a change of the momentum space topology is shown to be accurately described by a simple analytic model, thus providing a powerful means of determining the avalanche threshold for a range of model assumptions.

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Fusion Energy Sciences (FES) (SC-24)
OSTI Identifier:
1417822
Report Number(s):
LA-UR-17-28349
Journal ID: ISSN 0741-3335
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Plasma Physics and Controlled Fusion
Additional Journal Information:
Journal Volume: 60; Journal Issue: 2; Journal ID: ISSN 0741-3335
Publisher:
IOP Science
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; Magnetic Fusion Energy; runaway electrons; tokamak disruptions; Fokker–Planck equation

Citation Formats

McDevitt, Christopher J., Guo, Zehua, and Tang, Xian -Zhu. Relation of the runaway avalanche threshold to momentum space topology. United States: N. p., 2018. Web. doi:10.1088/1361-6587/aa9b3f.
McDevitt, Christopher J., Guo, Zehua, & Tang, Xian -Zhu. Relation of the runaway avalanche threshold to momentum space topology. United States. doi:10.1088/1361-6587/aa9b3f.
McDevitt, Christopher J., Guo, Zehua, and Tang, Xian -Zhu. 2018. "Relation of the runaway avalanche threshold to momentum space topology". United States. doi:10.1088/1361-6587/aa9b3f.
@article{osti_1417822,
title = {Relation of the runaway avalanche threshold to momentum space topology},
author = {McDevitt, Christopher J. and Guo, Zehua and Tang, Xian -Zhu},
abstractNote = {Here, the underlying physics responsible for the formation of an avalanche instability due to the generation of secondary electrons is studied. A careful examination of the momentum space topology of the runaway electron population is carried out with an eye toward identifying how qualitative changes in the momentum space of the runaway electrons is correlated with the avalanche threshold. It is found that the avalanche threshold is tied to the merger of an O and X point in the momentum space of the primary runaway electron population. Such a change of the momentum space topology is shown to be accurately described by a simple analytic model, thus providing a powerful means of determining the avalanche threshold for a range of model assumptions.},
doi = {10.1088/1361-6587/aa9b3f},
journal = {Plasma Physics and Controlled Fusion},
number = 2,
volume = 60,
place = {United States},
year = 2018,
month = 1
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on January 5, 2019
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