Assessing energy dependence of the transport of relativistic electrons in perturbed magnetic fields with orbit-following simulations
Journal article, 2020

Experimental observations, as well as theoretical predictions, indicate that the transport of energetic electrons decreases with energy. This reduction in transport is attributed to finite orbit width (FOW) effects. Using orbit-following simulations in perturbed tokamak magnetic fields that have an ideal homogeneous stochastic layer at the edge, we quantify the energy dependence of energetic electrons transport and confirm previous theoretical estimates. However, using magnetic configurations characteristic of JET disruptions, we find no reduction in runaway electron transport at higher energies, which we attribute to the mode widths being comparable to the minor radius, making the FOW effects negligible. Instead, the presence of islands and non-uniform magnetic perturbations are found to be more important. The diffusive-advective transport coefficients calculated in this work, based on simulations for electron energies 10 keV-100 MeV, can be used in integrated disruption modelling to account for the transport due to the magnetic field perturbations.

transport

plasma disruption

stochastic magnetic field

orbit-following

runaway electrons

Author

Konsta Särkimäki

Chalmers, Physics, Subatomic, High Energy and Plasma Physics

Ola Embréus

Chalmers, Physics, Subatomic and Plasma Physics

Eric Nardon

The French Alternative Energies and Atomic Energy Commission (CEA)

Tünde Fülöp

Chalmers, Physics, Subatomic, High Energy and Plasma Physics

Nuclear Fusion

0029-5515 (ISSN)

Vol. 60 12 126050

Subject Categories

Other Physics Topics

Fusion, Plasma and Space Physics

Condensed Matter Physics

DOI

10.1088/1741-4326/abb9e9

More information

Latest update

12/3/2020