RF Control of Impurity Transport

Abstract

Two types of radiofrequency control of impurity transport are proposed; one is the diffusion coefficient control by RF impurity-ion heating, and the other is based on particle flux carried by externally launched waves in a plasma. A simple fluid model provides a usefull expression for the particle flux density which is driven by low-frequency electrostatic waves in an inhomogeneous multi-ion-species plasma. Owing to selective outward flux induced by RF, the impurity diffusion diminishes or even reverses the direction of the inward collisional diffusion.