Analytical model for quasi-linear flow response to resonant magnetic perturbation in resistive-inertial and viscous-resistive regimes

TL;DR

This paper develops a comprehensive quasi-linear model for plasma flow response to resonant magnetic perturbations in tokamaks, derived from reduced MHD equations, unifying magnetic island and flow response analyses.

Contribution

It introduces a unified quasi-linear model for plasma response to RMPs derived entirely from two-field reduced MHD equations, clarifying physical origins of forces involved.

Findings

Model recovers previous plasma flow response models under certain conditions.

Physical origins of quasi-linear forces and moments are clarified.

The model is applicable in resistive-inertial and viscous-resistive regimes.

Abstract

In this work, a quasi-linear model for plasma flow response to the resonant magnetic perturbation (RMP) in a tokamak has been rigorously developed in the resistive-inertial (RI) and viscous-resistive (VR) regimes purely from the two-field reduced MHD model. Models for plasma response to RMP are commonly composed of equations for the resonant magnetic field response (i.e. the magnetic island) and the torque balance of plasma flow. However, in previous plasma response models, the magnetic island and the torque balance equations are often derived separately from reduced MHD and full MHD equations, respectively. By contrast, in this work we derive both the magnetic island response and the torque balance equations in a quasi-linear model for plasma flow response entirely from a set of two-field reduced MHD equations. Such a quasi-linear model can recover previous plasma flow response models within certain limits and approximations. Furthermore, the physical origins of quasi-linear forces and moments in the flow response equation are also accurately calculated and clarified self-consistently.