Kinetic modelling of runaway electrons in dynamic scenarios
Journal article, 2016

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 conservative collision operator 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 simpler avalanche model of Rosenbluth & Putvinskii [Nucl. Fusion 37, 1355 (1997)] can give very 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 an improved modelling of runaway-electron dynamics during disruptions or other dynamic events.

Author

Adam Stahl

Chalmers, Physics, Subatomic and Plasma Physics

Ola Embréus

Chalmers, Physics, Subatomic and Plasma Physics

Gergely Papp

Max Planck Society

M Landreman

University of Maryland

Tünde Fülöp

Chalmers, Physics, Subatomic and Plasma Physics

Nuclear Fusion

0029-5515 (ISSN) 1741-4326 (eISSN)

Vol. 56 11 112009- 112009

Driving Forces

Sustainable development

Areas of Advance

Energy

Roots

Basic sciences

Subject Categories

Fusion, Plasma and Space Physics

DOI

10.1088/0029-5515/56/11/112009

More information

Latest update

4/5/2022 6