Transport matrix for particles and momentum in collisional drift waves turbulence in linear plasma devices

摘要

The relationship between the physics of turbulent transport of particles and azimuthal momentum in a linear plasma device is investigated using a simple model with a background density gradient and zonal flows driven by turbulent stresses. Pure shear flow driven Kelvin-Helmholtz instabilities (k(parallel to) = 0) relax the flow and drive an outward (down gradient) flux of particles. However, instabilities at finite k(parallel to) with flow enhanced pumping can locally drive an inward particle pinch. The turbulent vorticity flux consists of a turbulent viscosity term, which acts to reduce the global vorticity gradient and the residual vorticity flux term, accelerating the zonal flows from rest. Moreover, we use the positivity of the production of fluctuation potential enstrophy to obtain a constraint relation, which tightly links the vorticity transport to the particle transport. This relation can be useful in explaining the experimentally observed correlation between the presence of E x B flow shear and the measured inward particle flux in various magnetically confined plasma devices. (C) 2016 AIP Publishing LLC.