Impurity transport driven by electrostatic turbulence in tokamak plasmas

Paper i proceeding, 2010

Impurity transport driven by electrostatic turbulence is analyzed in weakly-collisional tokamak plasmas using a semi-analytical model based on a boundary-layer solution of the gyrokinetic equation. Analytical expressions for the perturbed density responses are derived and used to calculate the stability boundaries, mode frequencies, growth rates and the quasilinear particle fluxes. Parametric dependencies of the above quantities with respect to impurity charge, effective charge, impurity density scale length, and collisionality, and the effect of the impurities on the stability boundaries, have been determined and compared with quasilinear gyrokinetic simulations with GYRO resulting in very good agreement. An analytical approximate expression of the zero-flux impurity density gradient is derived and used to discuss its parametric dependencies.