Promoted Plasma Generation For Laser-Driven Flyer By Mgal Hydride Films

MgAl hydride films with different hydrogen contents were fabricated in Ar and H-2 mixed atmosphere using magnetron sputtering. Neutron reflectometry was performed to measure hydrogen contents, which indicated that up to llatom% hydrogen was absorbed into MgAl. The MgAl hydride films were irradiated using pulsed lasers and the electron temperature and density of the generated plasma was measured. Results showed the electron temperature and density at delay time of 1 mu s were 7330 K, 7.9 x 10(15) cm(-3) and 8044 K, 9.0 x 10(15) cm(-3) for MgAl hydride films with 5atom% and 11atom% hydrogen, respectively. For comparison, the electron temperature and density for pure MgAl film were 5634 K and 6.9 x 10(15) cm(-3). Obviously, the electron temperature and density increases with the hydrogen content. Subsequently, the conversion ratio of the shock wave energy to the incident pulse energy were analyzed by investigating plasma induced shock wave evolution. The conversion ratio for MgAl hydride films with 5atom% and 11atom% hydrogen was 19.2% and 28.6%, which was 1.2 and 1.8 times of that for the MgAl film. Therefore, the MgAl hydride film promised to be a new class of material capable of promoting the plasma generation of the laser-driven flyers.