Analysis of Neutral Transport in GAMMA 10 SMBI Experiments

Abstract

Results of supersonic molecular beam injection (SMBI) into GAMMA 10 are described. By analyzing the two-dimensionalimage of the emission captured by a high-speedcamera, we investigated neutral transport during SMBI. The experimental results show that the degree of diffusion of the injected neutral particles decreases with increasing plenum pressure. By applying a three-dimensional Monte-Carlo simulation to GAMMA 10, we analyze the neutral-particle transport. The simulation given under the initial conditions of the conventional gas puffing could not reproduce the experimental results. Compared with experimental results, the results of simulation were too diffusive. The experimental SMBI results were roughly reproduced under more squeezed divergence angle of injected particles than that of a cosine distribution. These results reveal a difference between divergence angles for particles launched via SMBI and via conventional gas puffing.