Hybrid continuum/DSMC computation of rocket mode lightcraft flow in near space with high temperature and rarefaction effect

In this paper, we consider laser propulsion operating in near space (altitude of 20-100 km) where the ambient gas is rarefied . For the rocket mode, a dense gas is injected into the focused region to generate high temperature plasma by laser beam focusing. A hybrid continuum/DSMC method is used to simulate the unsteady high temperature continuum flow coupled with the rarefied ambient air. An order of magnitude analysis, based on a simplified physical analysis, is provided for the impulse coupling coefficient and specific impulse. For the rocket mode studied here, a specific impulse of 855 s is obtained.