1D model study on the effect of impurity radiation cooling in LHD SOL plasma

Abstract

Increasing heat load to plasma-facing walls in future fusion devices and reactors could exceed the engineering limit of the material if simple scaling is applied in size of device to realize sufficient energy confinement time. One of possible means to remove the heat in plasma is impurity gas puffing. In order to investigate the plasma response to the radiation cooling, a one dimensional steady-state two-fluid model has been developed to describe SOL plasma of LHD. Model equations were solved numerically for various neon density and three types of SOL plasma. Maximum neon density above which plasma does not sustain is found. Significant reduction of temperature and heat flux onto the divertor plate are found. It is confirmed that the neon gas puffing is an effective technique to reduce the heat load onto divertor plates. © 2012 The Japan Society of Plasma Science and Nuclear Fusion Research.