Influence of Single Pulse Energy on the Wave Structure of the Flow Field in Laser Propulsion
M. Wen, G-Y. Wang, Y-J. Hong, J-F. Ye and C-Y. Cui
Keeping the relative position between a lens and a flat target constant, wave structures of laser propulsion flow field under different pulse energy were studied with a high-speed shadowing system, in which wide regulation of a single pulse energy was realized by attenuation of silicon slice combinations. The blast wave velocities were obtained from sequential photographs of wave evolvement. The results indicated that the flow field expanded following an arc under three different energy conditions and there existed a slow change in the low-density and low-pressure air mass. The whole blast wave velocities increased as the energy increased. The elapsed time for the blast wave velocity decreased to a sonic one and was longer as the energy was increased. The results were analysed based on the relative theory of the blast wave. The laser propulsion performance was estimated and was consistent with the measured results of the impulse using a parabolic device.
Keywords: Laser propulsion, pulse energy, flow field, wave structure, blast wave velocity.