Microtearing Modes in Reversed Field Pinch Plasmas

TL;DR

This paper investigates microtearing modes as the primary turbulence mechanism in RFX-mod reversed field pinch plasmas, linking strong temperature gradients to these instabilities and their impact on electron thermal conductivity.

Contribution

It identifies microtearing modes as the dominant turbulence in RFX-mod plasmas with strong temperature gradients, supported by gyrokinetic calculations and quasi-linear analysis.

Findings

Microtearing modes dominate turbulence in the studied plasma region.

Electron thermal conductivity estimates match experimental data.

Strong temperature gradients trigger microtearing instabilities.

Abstract

In the reversed field pinch RFX-mod strong electron temperature gradients develop when the Single-Helical-Axis regime is achieved. Gyrokinetic calculations show that in the region of the strong temperature gradients microtearing instabilities are the dominant turbulent mechanism acting on the ion Larmor radius scale. The quasi-linear evaluation of the electron thermal conductivity is in good agreement with the experimental estimates.