Gyrofluid computation of magnetic perturbation effects on turbulence and edge localized bursts

TL;DR

This paper uses gyrofluid simulations to study how resonant magnetic perturbations affect turbulence and edge localized bursts in tokamak plasmas, revealing that turbulence remains dominant in transport and RMPs can destabilize edge profiles.

Contribution

It introduces a nonlinear gyrofluid model that accounts for plasma response to RMPs and examines their impact on turbulence and edge instabilities in tokamaks.

Findings

Turbulent convection dominates radial transport even with large RMPs.

Stationary convective structures form, degrading edge profiles.

RMPs can cause mode locking and destabilize edge profiles.

Abstract

The effects of non-axisymmetric resonant magnetic perturbation fields (RMPs) on saturated drift-wave turbulence and on ballooning mode bursts in the edge pedestal of tokamak plasmas are investigated by numerical simulations with a nonlinear six-moment electromagnetic gyrofluid model including zonal profile evolution. The vacuum RMP fields are screened by plasma response currents, so that magnetic transport by perturbed parallel motion is not significantly changed. Radial transport of both particles and heat is dominated by turbulent convection even for large RMP amplitudes, where formation of stationary convective structures leads to edge profile degradation. Modelling of ideal ballooning mode unstable edge profiles for single bursts including RMP fields causes resonant mode locking and destabilization.