Ion orbit loss and pedestal width of H-mode tokamak plasmas in limiter geometry

Abstract

A simple analytical model is proposed to analyze the effects of ion orbit loss on the edge radial electric field in a tokamak with limiter configuration. The analytically predicted edge radial electric field is consistent with the H-mode experiments, including the width, the magnitude, and the well-like shape. This model provides an explanation to the H-mode pedestal structure. Scaling of the pedestal width based on this model is proposed.