Structure-preserving electromagnetic–kinetic simulations of lower hybrid-wave injection and current drive

In this article, we present a first-principles electromagnetic–kinetic simulation of the slow-wave branch of the lower hybrid waves (LHWs) in electron–deuterium plasmas with real ion–electron mass ratios. Several models of two-dimensional slab configuration containing a grill antenna are constructed using different plasma parameters. Based on our recently developed fully kinetic charge-conservative electromagnetic non-canonical symplectic particle-in-cell method, we studied the coupling, propagation, absorption and current driving effect of LHWs in hot plasmas. The results for the coupling coefficient of the grill antenna, accessibility condition, and electron Landau damping rate show good agreement with theory and previous simulation. The long-term non-linear energy and current deposition of propagating LHWs are also presented, which show a decrement of heating and current-driving efficiency compared with the linear theoretical prediction. The collision effect between electrons and ions is shown to be important for actually driving the current. The relation between the density of the current generated and the amplitude of the LHW is given, which shows a qualitative agreement with the 1D theoretical prediction. (paper)