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

TL;DR

This paper compares two analytical models, the coherent mode coupling and wave kinetic equation models, for studying zonal flow generation in ITG turbulence, highlighting their qualitative agreement despite different assumptions.

Contribution

It provides a comparative analysis of two distinct models for zonal flow generation in ITG turbulence, which has not been extensively done before.

Findings

Both models produce qualitatively similar results.

The models differ in their spectral assumptions.

The comparison enhances understanding of multi-scale interactions.

Abstract

During the past years the understanding of the multi-scale interaction problems have increased significantly. However, at present there exists a range of different analytical models for investigating multi-scale 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 give qualitatively the same results even though the assumption on the spectral difference is used in the (WKE) approach.