Poloidal rotation driven by electron cyclotron resonance wave in tokamak plasmas

Qing Zhou,Yubin Gong,Xinliang Xu,Lin Nie,Jie Wen,Changjian Tang

doi:10.1063/1.5006501

Abstract

The poloidal electric filed, which is the drive field of poloidal rotation, has been observed and increases obviously after the injection of electron cyclotron resonance wave in HL-2A experiment, and the amplitude of the poloidal electric field is in the order of 103 V/m. Through theoretical analysis using Stringer rotation model, the observed poloidal electric field is of the same order as the theoretical calculation value. In addition, the magnetic pump damping which would damp the poloidal rotation is calculated numerically and the calculation results show that the closer to the core plasmas, the stronger the magnetic pump damping will be. Meanwhile, according to the value of the calculated magnetic pump damping, the threshold of the poloidal electric field which could overcome magnetic pump damping and drive poloidal rotation in tokamak plasmas is given out. Finally, the poloidal rotation velocity over time at different minor radius is studied theoretically.

Highlights

There are two types of rotation in Tokamak plasmas, namely toroidal rotation[12] and poloidal rotation.[6,7,8,9,10,11] The toroidal rotation and poloidal rotation are very important for the plasma confinement.[13,18] without external drive, spontaneous poloidal rotation in Tokamak plasmas would be hard to generate because of the magnetic pump damping
In order to drive the poloidal rotation in the core plasmas, the electron cyclotron resonance wave (ECRW) is utilized owing to its good accessibility and suitability for local heating
The injection of electron cyclotron resonance waves and neutral beam in shot 31193 is shown in figure 1 (b) where the above curve is the relation of the power of electron cyclotron resonance wave to time and the following one is the relation of the power of neutral beam injection to time

Summary

INTRODUCTION

There are two types of rotation in Tokamak plasmas, namely toroidal rotation[12] and poloidal rotation.[6,7,8,9,10,11] The toroidal rotation and poloidal rotation are very important for the plasma confinement.[13,18] without external drive, spontaneous poloidal rotation in Tokamak plasmas would be hard to generate because of the magnetic pump damping. Previous study shows that with Alfven wave drive[1] and fast wave drive,[2] the poloidal rotation can be driven in the edge of the plasmas.[5] In order to drive the poloidal rotation in the core plasmas, the electron cyclotron resonance wave (ECRW) is utilized owing to its good accessibility and suitability for local heating. It is well known[17,19,20] that the injection of ECRW can produce a poloidal asymmetric particle profile, namely inhomogeneous ion accumulation, which forms a poloidal electric field.

EXPERIMENTAL OBSERVATION OF POLOIDAL ROTATION

THEORETICAL ANALYSIS OF POLOIDAL ROTATION

CONCLUSIONS