Turbulent relaxation patterns in SOL plasma

Abstract

Relaxations of localized over-density in a plane transverse to the magnetic field are numerically
investigated under the effect of drift-wave and interchange drives in SOL conditions. Such a controlled
departure from thermodynamic equilibrium allows the investigation of fundamental processes
at play in cross-field transport. Interchange instabilities generate ballistic outward radial flux with
low amplitude zonal flow patterns, whereas drift-wave instabilities result in symmetric radial flux
with large amplitude zonal flow patterns. When both instabilities are considered, the combined
effects tend to favor drift-waves, leading to a weaker outward flux with larger zonal flow patterns.