Thermal blooming of pulsed focused gaussian laser beams

Thermal blooming of a pulsed, focused Gaussian laser beam in a gas is studied for a specific model of gaseous heating. Analytic results in the limit of times both long and short compared with the sound transit time across any part of the beam are presented as irradiance profiles at any range as a function of time. Experiments that can be done with present laser technology to test the theoretical predictions are suggested.