Laser self-focusing in the atmosphere

The theory of self-focusing has been applied to beams propagating in the atmosphere. The effects of density variation, absorption, and air breakdown which limit the self-focusing through power driven instabilities are estimated. It is found that laser pulses whose pulse lengths are between 10 ns and 10 micros with powers from 10(2)P(c) to 10(3)P(c) have a chance to self-focus. Here P(c) is the critical power for self-focusing in an ideal nonattenuating medium with a nonlinear index of refraction.