抄録
A high-speed wind tunnel, by use of a Ludwieg tube, has been successfully developed for a highly-repetitive discharge-pumped excimer laser, the characteristics of which have been evaluated. This apparatus allows the gas flow of velocity -200m/s and pressure -294kPa. As a result of the expansion cooling, the temperature of the gas is lowered to -254K from the incident room temperature. The excimer laser flow has been simulated by solving the unsteady two-dimensional Euler equations, and aerodynamic effects of the highly-repetitive pulse discharge are investigated. A large density perturbation appears in the main discharge region when the main discharge occurs and/or the gas heated by the upstream preionization discharge arrives at the main discharge region. The high-speed gas flow sweeps the main part of the density perturbation caused by the main discharge during the successive discharge pulses. The temperature dependence of the XeCl-lasing characteristics under the expansion cooling is also simulated. The simulation has indicated the enhancement of the laser output in the lower temperature.
