Role of Edge Stochastic Layer in Density Pump-out by Resonant Magnetic Perturbations

The role of the edge stochastic layer on particle transport is addressed in DIII-D plasmas with applied Resonant Magnetic Perturbations (RMPs) causing density pumpout. Using an analytical model that adds the stochastic parallel transport of electrons [R. Harvey et. al., 1981 Phys. Rev. Lett. 47 (1981)] to the fluid equations the ambipolar radial electric field and particle flux are calculated self-consistently. In this model the nonambipolar electron particle flux, driven by the stochastic magnetic field, is predominantly balanced by the nonambipolar perpendicular ion flux, driven by toroidal viscosity, across a narrow stochastic layer of order 2 percent of the plasma radius (0.98