Study Of Lower Hybrid Wave Current Drive And Heating In EAST Plasma Edge

Lower hybrid wave current drive(LHCD)is one of the most effective non-inductive current driving method,a key tool to achieving long pulse steady-state operation for EAST.In tokamak high density experiments,the parameters of plasma edge play an important role in LHCD.EAST LHCD experiments evidence that lower hybrid waves drive current and deposit power in plasma edge.The study of lower hybrid wave current drive and heating in plasma edge is beneficial for promoting experimental studies,maintaining tokamak long pulse steady-state operation and peaceful using fusion energy.The basic theory of lower hybrid propagation and current drive is firstly introduced in this paper.Then effect of the scrape off layer(SOL)for lower hybrid wave absorption in EAST and Effect of lower hybrid wave current drive with high components N_? on EAST are studied by physical analysis and numerical simulation.The study in this paper is summarized as the following two sections:(1)The propagation and absorbed power of high N_? lower hybrid waves in tokamak plasma is studied by the propagated condition and Landau damping condition.The results show high N_? lower hybrid waves can't penetrate to core of plasma because the power of those waves is absorbed at plasma edge by Landau damping;those waves deposit power and drive current at plasma edge.High N_? lower hybrid waves were simulated in EAST plasma by LSC code.The numerical results indicate the lower hybrid wave with initial N_?=-6,-7 and-8 can drive current which is~kA magnitude and opposite direction of plasma current in the region of the normalized radius from 0.7 to 1.0.The closer distance between current drive and wall can been obtained in higher N_? or electron temperature in plasma edge.(2)The lower hybrid wave behaviors were simulated in the SOL by GENRAY code combining CQL3D code are comparatively analyzed.The results indicate that the propagation of lower hybrid waves could not been ignored in high density EAST parameter plasmas due to the losses power in the SOL.The ray trajectories are changed upshift of N_? decrease by multi-reflection in plasma edge from the numerical results.The study of lower hybrid wave absorption in the SOL with different SOL density and temperature by simulation show:The power loss of lower hybrid wave by collision and propagated region in the SOL increase with higher SOL electron density.Increasing electron temperature in high density SOL parameter results in lower power loss by collision in the SOL;the main source of power deposition in the SOL is power loss by collision.