Laser-induced pressure transfer in a regularly structured medium

The results of computational and theoretical studies of the spatiotemporal evolution of the plasma produced by laser heating a regularly structured absorber, which is a set of equidistantly located flat layers separated by low-density gaps, are presented. The features of laser-induced pressure transfer through such a medium into an adjacent solid indicator-target are investigated. It is shown that if the average density of the medium exceeds the critical plasma density, pressure is transferred through successive collisions of the absorber walls. In the case of a subcritical average density of the absorber, the shock wave in the indicator-target is initially induced by the impact of laser radiation transmitted through the absorber on it, and only then by the impact of the ablated absorber walls. It was shown that the maximum pressure time dependency is characterized by the existence of a short peak and then a long plateau. At a laser pulse intensity of 1014 W/cm2, the peak pressure achieves values of several hundred Mbar, which is maintained during several tens of ps, and pressure on a plateau—several tens of Mbar for several hundred ps. The possibilities of using such regularly structured absorbers for practical applications related to laser-driven shock waves for the investigation of matter properties and laser acceleration of high-energy charged particles are discussed.