Effect of Magnetic Configuration on the Neutral Particle Recycling in Compact Helical System

In devices such as Stellarator/Heliotron, nested magnetic surfaces are surrounded by the so-called separatrix layer, which consists of open field lines with various connection length to the vacuum chamber wall and/or divertor plates. In this paper, we study the strike point distribution of field lines on Compact Helical System chamber wall, especially under divertor configuration. Then, by using these distribution as the measure of neutral recycling source, Monte Carlo simulation of 3-D neutral transport is done. The results are compared with those obtained for different magnetic configuration.