Kinetic modelling of runaway electrons in dynamic scenarios

A. Stahl, O. Embréus, G. Papp, M. Landreman, T. Fülöp

Research output: Contribution to journalArticle

28 Citations (Scopus)

Abstract

Improved understanding of runaway-electron formation and decay processes are of prime interest for the safe operation of large tokamaks, and the dynamics of the runaway electrons during dynamical scenarios such as disruptions are of particular concern. In this paper, we present kinetic modelling of scenarios with time-dependent plasma parameters; in particular, we investigate hot-tail runaway generation during a rapid drop in plasma temperature. With the goal of studying runaway-electron generation with a self-consistent electric-field evolution, we also discuss the implementation of a collision operator that conserves momentum and energy and demonstrate its properties. An operator for avalanche runaway-electron generation, which takes the energy dependence of the scattering cross section and the runaway distribution into account, is investigated. We show that the simplified avalanche model of Rosenbluth and Putvinskii (1997 Nucl. Fusion 37 1355) can give inaccurate results for the avalanche growth rate (either lower or higher) for many parameters, especially when the average runaway energy is modest, such as during the initial phase of the avalanche multiplication. The developments presented pave the way for improved modelling of runaway-electron dynamics during disruptions or other dynamic events.

Original languageEnglish
Article number112009
JournalNuclear Fusion
Volume56
Issue number11
DOIs
Publication statusPublished - Jul 22 2016

Fingerprint

avalanches
kinetics
operators
plasma temperature
multiplication
scattering cross sections
energy
fusion
momentum
collisions
electric fields
decay

Keywords

  • avalanche generation
  • Fokker-Planck equation
  • hot-tail generation
  • linearized collision operator
  • runaway electrons

ASJC Scopus subject areas

  • Nuclear and High Energy Physics
  • Condensed Matter Physics

Cite this

Kinetic modelling of runaway electrons in dynamic scenarios. / Stahl, A.; Embréus, O.; Papp, G.; Landreman, M.; Fülöp, T.

In: Nuclear Fusion, Vol. 56, No. 11, 112009, 22.07.2016.

Research output: Contribution to journalArticle

Stahl, A, Embréus, O, Papp, G, Landreman, M & Fülöp, T 2016, 'Kinetic modelling of runaway electrons in dynamic scenarios', Nuclear Fusion, vol. 56, no. 11, 112009. https://doi.org/10.1088/0029-5515/56/11/112009
Stahl, A. ; Embréus, O. ; Papp, G. ; Landreman, M. ; Fülöp, T. / Kinetic modelling of runaway electrons in dynamic scenarios. In: Nuclear Fusion. 2016 ; Vol. 56, No. 11.
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