Picosecond Interferomatric Studies of CO₂ Laser Produced Plasmas

Abstract

It has recently become apparent that the interaction of intense, shortpulse, CO₂ laser radiation with matter is dominated by collisionless absorption processes which couple energy primarily into fast electrons. This quickly leads to the formation of a two component plasma system with a relatively long lifetime, high density, thermal plasma adjacent to the solid target, surrounded by a much more transient collisionless superthermal plasma which rapidly propagates out of the interaction region. The diagnosis of these two regimes with high spatial and temporal resolution can provide considerable insight into the interaction physics relevant to current laser fusion studies.