Runaway electron losses caused by resonant magnetic perturbations in ITER

Abstract

Disruptions in large tokamaks can lead to the generation of a relativistic runaway electron beam that may cause serious damage to the first wall. To suppress the runaway beam the application of resonant magnetic perturbations (RMPs) has been suggested. In this work we investigate the effect of RMPs on the confinement of runaway electrons by simulating their drift orbits in magnetostatic perturbed fields and calculating the transport and orbit losses for various initial energies and different magnetic perturbation configurations. In the simulations we model the ITER RMP configuration and solve the relativistic, gyro-averaged drift equations for the runaway electrons including a time-dependent electric field, radiation losses and collisions. The results indicate that runaway electrons are rapidly lost from regions where the normalized perturbation amplitude δB/B is larger than 0.1% in a properly chosen perturbation geometry. This applies to the region outside the radius corresponding to the normalized toroidal flux ψ = 0.5.