Effects of radial electric field on ion temperature gradient driven mode stability

TL;DR

This paper investigates how a radial electric field influences the stability of ion-temperature gradient driven modes using gyrokinetic theory, revealing that zero frequency electric fields can significantly stabilize these modes.

Contribution

It provides a detailed analysis of the stabilizing effect of radial electric fields on ITG modes, incorporating finite-orbit-width effects and mode structure modifications.

Findings

Zero frequency radial electric fields can significantly stabilize ITG modes.

Density perturbations have little effect on ITG stability due to finite-orbit-width effects.

Parallel mode structure is slightly affected by the electric field-induced density modulation.

Abstract

The local stability of ion-temperature gradient driven mode (ITG) in the presence of a given radial electric field is investigated using gyrokinetic theory and ballooning mode formalism with toroidal effect accounted for. It is found that, zero frequency radial electric field induced poloidal rotation can significantly stabilize ITG, while the associated density perturbation has little effect on ITG stability due to the modification of finite-orbit-width effect. However, the parallel mode structure is slightly affected due to the evenly symmetric density modulation of ZFZF.