Laser induced shock studies at RRCAT, Indore

Abstract

The knowledge of material response under shock compression is important in terms of proper understanding of the process and in view of the wide range of technological applications associated with it. At the Laser Plasma Division, RRCAT, Indore, among other things, we are also involved in studying the material response from two different perspectives. On one front, we have developed capability for acquiring Equation of State (EOS) of materials using laser generated shock waves with long pulse lasers (>200 ps). On the other front, we have started shock experiments on single crystals using time resolved x-ray diffraction technique, using ultra-short pulse lasers (< 1 ps). In these initial experiments, characteristic sub-picosecond, high brightness Kα x-ray pulses generated by Ti: sapphire femtosecond laser produced plasmas of different target materials (Ti, Fe, and Cu) were used to probe the effect of compression generated by moderately intense (GW/cm2) sub-nanosecond laser (200 ps) pulse irradiation on the crystal surface. The dynamics of the shock propagation is manifested in terms of the temporal evolution of the rocking curve of shocked sample. The shock velocity deduced from these measurements is 12 km/s, consistent with the predicted velocities and probe depth. The observed maximum compression is 0.4 % which corresponds to a pressure of 0.8 GPa.