An advection-diffusion model for cross-field runaway electron transport in perturbed magnetic fields
Journal article, 2016

Disruption-generated runaway electrons (RE) present an outstanding issue for ITER. The predictive computational studies of RE generation rely on orbit-averaged computations and, as such, they lack the effects from the magnetic field stochasticity. Since stochasticity is naturally present in post-disruption plasma, and externally induced stochastization offers a prominent mechanism to mitigate RE avalanche, we present an advection-diffusion model that can be used to couple an orbit-following code to an orbit-averaged tool in order to capture the cross-field transport and to overcome the latter's limitation. The transport coefficients are evaluated via a Monte Carlo method. We show that the diffusion coefficient differs significantly from the well-known Rechester-Rosenbluth result. We also demonstrate the importance of including the advection: it has a two-fold role both in modelling transport barriers created by magnetic islands and in amplifying losses in regions where the islands are not present.

runaway electron

radial transport

stochastic magnetic field

diffusion

advection

Author

K. Sarkimaki

Aalto University

E. Hirvijoki

Princeton University

J. Decker

Swiss Federal Institute of Technology in Lausanne (EPFL)

J. Varje

Aalto University

Taina Kurki-Suonio

Chalmers, Physics, Subatomic and Plasma Physics

Plasma Physics and Controlled Fusion

0741-3335 (ISSN) 1361-6587 (eISSN)

Vol. 58 12

Subject Categories

Fusion, Plasma and Space Physics

DOI

10.1088/0741-3335/58/12/125017

More information

Latest update

11/5/2020