Diagnostics and Improvement of the Velocity and Density Characteristic of Deuterium/Hydrogen Supersonic Molecular Gas Jet

摘要

The detailed evolution process of deuterium and hydrogen supersonic molecular beam (SMB) was probed by one simple method based on the microphone. The velocity of the beam was measured by time-of-flight method, and the density was investigated by comparing the radial profiles of the SMB with the total amounts of molecules in the gas jet. The velocity and number density of deuterium SMB generated from a cylindrical nozzle were tested to be 1100m/s and 3.6E15cm(-3) at axial distance of 1700mm and stagnation pressure of 50bar, which was about 30% lower than that of hydrogen SMB generated from the same nozzle, and was in consistent with the total number of molecules in deuterium gas jet that was 30% smaller than hydrogen. It is found that the use of a cylindrical nozzle and arrangement of a special skimmer can increase the central density of SMB by about 150% and 45%, while the utilization of one conical nozzle would increase the velocity of the SMB by 13%, these results could give great help in the SMB diagnostics and fueling of the nuclear fusion experiments.