Interaction of scrape-off layer currents with magnetohydrodynamical instabilities in tokamak plasmas

Abstract

A simple theoretical model is developed which describes how current eddies are excited in the scrape-off layer (SOL) of a large-aspect-ratio, low- Β, circular cross-section tokamak by time-varying magnetohydrodynamical instabilities originating from within the plasma. This model is used to study the interaction of SOL currents with tearing modes and resistive wall modes in a typical tokamak plasma. SOL currents are found to be fairly effective at braking the rotation of tearing modes, and to have a significant destabilizing effect on resistive wall modes. © 2007 American Institute of Physics.