Particle pinch and collisionality in gyrokinetic simulations of tokamak plasma turbulence
The generic problem of how, in a turbulent plasma, the experimentally relevant conditions of a particle flux very close to the null are achieved, despite the presence of strong heat fluxes, is addressed. Nonlinear gyrokinetic simulations of plasma turbulence in tokamaks reveal a complex dependence of the particle flux as a function of the turbulent spatial scale and of the velocity space as collisionality is increased. At experimental values of collisionality, the particle flux is found close to the null, in agreement with the experiment, due to the balance between inward and outward contributions at small and large scales, respectively. These simulations provide full theoretical support to the prediction of a peaked density profile in a future nuclear fusion reactor.
Keywords: pinch effect ; plasma collision processes ; plasma simulation ; plasma transport processes ; plasma turbulence ; Tokamak devices ; Profile Peaking ; Density Peaking ; Asdex Upgrade ; Mode Plasmas ; Transport ; Heat
Record created on 2010-05-18, modified on 2016-08-08