Generation of toroidal rotation by gas puff. Simulations of MAST experiments with B2SOLPS5.0

Simulations have been performed to investigate the impact of gas puffing position on plasma toroidal rotation. It was demonstrated that inboard puffing generates counter-current rotation in agreement with experimental observations. On the basis of the simulations a physical model was put forward, which is based on momentum transport by vertical ∇B drifts and anomalous radial transport. Toroidal rotation is generated mainly due to radial transport of the inboard/outboard particle fluxes by ∇B drifts. Its value depends on the location, radial and poloidal dimensions of the ionization source on the closed field lines, increases linearly with the ion temperature and plasma density and is inversely proportional to the plasma current.