Temperature and mechanics effect measurement of plasma induced by laser ablating hard aluminum

In order to study the mechanism of laser interacting with materials in laser propulsion technique, the parameters related to plasma state and mechanics are needed. The plasma spectra and temperature are measured by laser-induced plasma spectroscopy, the mechanical parameters are obtained by impulse pendulum, as a passive Q-switch solid laser is ablating hard aluminum. The experimental results demonstrate that the plasma temperature on material surface declines with time in quadratic curve mode under laser power density of 0.534 x 108 W/cm2. Changing the laser power density around the material plasma ignition threshold, it is found that the plasma temperature and the momentum coupling coefficients increase with the increase of the power density, they reach the maximum as the power density reaches the plasma ignition threshold. After this, though the power density rises, the plasma shielding effect on energy leads to the decrease of the plasma temperature, the kinetic energy on material surface, and the coupling impulse of material. (authors)