Turbulence Simulations of X-point Physics on the L-H Transitions

摘要

We show that the resistive X-point mode is dominant mode in boundary plasmas in X-point divertor geometry. The poloidal fluctuation phase velocity from the resistive X-point turbulence shows experimentally measured structure across separatrix. The fluctuation phase velocity is larger than E x B velocity both in L and H mode phases, by at least a factor of two. We also demonstrate that there is a strong poloidal asymmetry of particle flux in the proximity of the separatrix. Turbulence suppression in the L-H transition results when sources of energy and particles drive sufficient gradients as experiments.