Analysis of high-field side plasma instabilities in tokamak edge

TL;DR

This paper investigates the stability of plasma in tokamak edge regions, focusing on high-field side instabilities, using analytical and numerical models to understand turbulence and transport phenomena.

Contribution

It provides a detailed analysis of drift-resistive-ballooning mode instabilities on the high-field side, combining analytical and numerical approaches to advance understanding of edge plasma behavior.

Findings

High-field side plasma fluctuations are suppressed in balanced double-null configurations.

Steep density profiles on high-field side can drive strong instabilities.

Analytical and numerical models reveal characteristics of turbulence and transport in the edge plasma.

Abstract

Balanced double-null configurations are of general interest for boundary plasma physics, and they have been proposed for some future designs. Experimental observations demonstrate absence of plasma fluctuations in tokamak high-field side scrape-off layer in a balanced double-null configuration [Smick et al 2013 Nucl. Fusion 53 023001], and it is commonly assumed that plasma instabilities are suppressed on high-field side in the edge plasma due to the stabilizing effect of magnetic curvature. At the same time, the experimental evidence points to extremely steep plasma density profiles on high-field side, which should provide a strong instability drive. In the present study, the drift-resistive-ballooning mode instability model is investigated analytically and numerically to determine the characteristics of plasma instabilities, turbulence, and transport in tokamak scrape-off layer on high-field side.