Global 3D two-fluid simulations of the tokamak edge region: Turbulence, transport, profile evolution, and spontaneous E × B rotation

Abstract

We present global two-fluid simulations of L-mode edge tokamak plasma turbulence and profile evolution including both closed field lines and the scrape-off-layer. We consider a shifted-circle magnetic configuration with realistic Alcator C-Mod inner wall limited discharge parameters. The dominant driver of turbulence in the simulations is the resistive ballooning mode. We observe spontaneous E × B rotation in the electron diamagnetic drift direction in the closed flux region in all cases. We explain this based on the steady state ion continuity relation ∇·nv→i≈0. We find that the E × B rotation in the closed flux region mostly cancels the ion diamagnetic drift as H-mode-like regimes are approached and exceeds it by a factor of 2 or more at lower temperatures due to parallel ion flows.