Plasma Turbulence in the Scrape-off Layer of the ISTTOK Tokamak

TL;DR

This paper investigates plasma turbulence in the scrape-off layer of the ISTTOK tokamak using theoretical models and simulations, identifying key instabilities and asymmetries, and comparing results with experimental data.

Contribution

It provides a comprehensive analysis of turbulence mechanisms in ISTTOK's SOL using drift-reduced Braginskii equations, including linear and non-linear simulations in 2D and 3D.

Findings

Identified dominant linear instabilities driving turbulence.

Revealed asymmetry between low-field and high-field sides.

Compared simulation results with experimental measurements.

Abstract

The properties of plasma turbulence in a poloidally limited scrape-off layer (SOL) are addressed, with focus on ISTTOK, a large aspect ratio tokamak with a circular cross section. Theoretical investigations based on the drift-reduced Braginskii equations are carried out through linear calculations and non-linear simulations, in two- and three-dimensional geometries. The linear instabilities driving turbulence and the mechanisms that set the amplitude of turbulence as well as the SOL width are identified. A clear asymmetry is shown to exist between the low-field and the high-field sides of the machine. A comparison between experimental measurements and simulation results is presented.