This paper describes a performance of 100 J-class KrF laser system "GARPUN" intended for target irradiation experiments by 100 ns pulses. A controllable space-time intensity distribution in a focal spot reaching 5* 1O2 W/cm2 produced megabar ablation pressure, which initiated conical shock wave in solids. It propagated in a quasi-steady manner together with an ablation front that resulted in anomalous high penetration rate of laser radiation throughout the matter. Long-time sample loading together with strong tangential shear flow of compressed layers produced favorable conditions for pressure-induced transformation of the pyrolytic graphite into a diamond-like phase by martensitic mechanism.

No abstract

Explosives or explosive-accelerated plane flyers can pressurize the examined material up to hundreds kilobars, but it is heated significantly by a shock wave. If a phase transition occurs during the sample loading, a high post-shock temperature will influence a new phase1. Laser irradiation of targets may produce ablation pressures in a multi-megabar range with temperature control by means of time profiling of a laser pulse or using an appropriate target design. This offers new opportunities in investigations of equation of state and phase transformations in compressed materials, in particular, diamond production by laser compression of graphite targets2.

No abstract

No abstract