Experimental Studies On The Effect Of Plasma Toroidal Rotation With Lower Hybrid Current Drive On EAST

Plasma rotation and its shear can reduce the magnetohydrodynamic instabilities and enhance the confinement.The research of plasma rotation is one of the hot topics in magnetic confinement nuclear fusion.Due to the larger size and higher plasma density of the international thermonuclear experimental reactor and the future fusion reactor,it is difficult to effectively drive the plasma rotation,which requires MV level beam energy and correspondingly better neutral beam power.Lower hybrid current drive?LHCD?has been proposed as a possible means of rotation driving on a future fusion reactor.Exploring the mechanisms of LHCD rotation driving on the current tokamaks can provide important reference for future reactors.This paper mainly deals with the analysis and processing of the existing low hybrid driven rotating experimental data.And on the basis of the original experimental data to carry out a new experiment to further explore its driving rotation mechanism.In this paper,we mainly analyze the toroidal rotation of plasma driven by LHCD under different background plasma.On EAST,at the lower current,the effects of different LHCD power on plasma toroidal rotation under ohmic background plasma are analyzed.Higher power LHCD has better driving efficiency.The effect of safety factor?q?profile on toroidal rotation is also presented.LHCD can change the profile of safety factor due to current drive.It was found when the power excess1.4MW,the q profile remain unchanged and the rotation also changes only very slightly with LHCD power,suggesting a close relationship between current profile and rotation.Under the background plasma of electron cyclotron resonance heating,the influence of LHCD on the plasma toroidal rotation is analyzed.The plasma toroidal rotation driven by LHCD is researched,under the background plasma of neutral beam inject.The experimental results of counter-current plasma rotation driven by LHCD on EAST are presented for the first time.Discussed possible reasons of counter-current rotation drive.In order to further analyze the dynamic process of plasma toroidal rotation driven by lower hybrid current drive on EAST,toroidal momentum transport due to LHCD is deduced using modulated LHCD power injection.Based on the momentum balance equation,the toroidal momentum diffusion coefficients??_??and the toroidal momentum pinch coefficients(V_pinch)are obtained by the method of separation of variables and Fourier analysis for the region where the external momentum source can be ignored.It was found that the momentum diffusion coefficient??_??and momentum pinch coefficient(V_pinch)tended to increase from the core to the outer region.This is consistent with the characteristic that the toroidal rotation velocity changes first at the outer region and then propagates to the core when the toroidal rotation is driven by LHCD.