Two-dimensional ray-trace calculations of thermal whole beam self-focusing

Abstract

Thermal self-focusing of laser light may be significant when a plasma is irradiated with short-wavelength laser light. Self-focusing magnifies the light intensity which can increase absorption by plasma waves (producing hot electrons which may cause preheat), could increase scattering, and could be a perturbation source for the Rayleigh–Taylor instability. We use two-dimensional hydrodynamic simulations to characterize thermal self-focusing for parameters of interest to laser fusion applications, and present a simple model. A diverging beam is shown to reduce the self-focusing.