Interaction of laser radiation with a dense gas target

An investigation was made of the interaction of a nanosecond laser pulse with a 'puff' gas target at gas densities sufficient for the formation of a critical-density plasma. The parameters of the laser plasma formed in the central interaction region and at its periphery were determined by x-ray spectroscopic methods. The formation of a plasma channel was observed and it was attributed to self-focusing of the laser radiation in the ionised gas.