Effects of high temperature flowfields around hypersonic air vehicles on laser lethality

The effects of high temperature flowfields around hypersonic air vehicles on laser lethality have been analysed in the case of the American Airborne Laser(ABL) system, including the effects of gas breakdown, plasma shielding and ablation smoke absorption. It is shown that, the electron number density in flowfields is generally less than 1017 cm-3 which can not result in plasma shielding. The plasma shielding of high pressure flowfields (above around 10 MPa) may be obvious only within the transmission distance of 0.5 km and only for broad pulse duration which may rarely happen in battlefield. The ablation products can not result in extinction to laser emission when the ablation mass flux nondimensioned by free stream flux is less than around 10-2 and the fli