Turbulence driven tearing modes in a tokamak plasma

Abstract

The influence of a random spectrum of lower hybrid waves on the evolution of tearing modes in a tokamak plasma is investigated. For rather modest levels of fluctuations, it is found that new tearing instabilities driven by turbulence are excited with significantly enhanced growth rates and comparable real frequencies. The growth rates for the new m = 1 and m = 2 modes vary as fractional powers of τR and δ, where τR is the turbulence induced diffusion time and δ is the ratio of Alfvénic time to the ion gyration period.