Comparison of multiscale analysis models applied to zonal flow generation in ion-temperature-gradient mode turbulence

Abstract

During the past years the understanding of the multiscale interaction problems have increased significantly. However, at present there exists a range of different analytical models for investigating multiscale interactions and hardly any specific comparisons have been performed among these models. In this work, two different models for the generation of zonal flows from ion-temperature-gradient (ITG) background turbulence are discussed and compared. The methods used is the coherent mode coupling model and the wave kinetic equation model (WKE). It is shown that the two models qualitatively give the same results even though the assumption on the spectral difference is used in the WKE approach.