Critical-Density Scale-Length Measurements in Laser-Produced Plasmas

Abstract

Inhomogeneity scale lengths between critical and quarter-critical densities have been obtained by photographing laser-produced plasmas in emitted light at twice and three-halves the laser frequency. The displacements of the harmonic-light images were measured on photographs taken from a position below spherical targets irradiated by four Nd: glass-laser beams. Over the range of 5 to 20 J absorbed (in 200 to 600 psec) by 70-100-\ensuremath{\mu}m-diam glass shells, this scale length increased linearly from 10 to 30 \ensuremath{\mu}m.