The effect of ambient pressure on laser-induced plasmas in air

A detailed investigation of the effect of ambient pressure in the range of 0.1 to 1.0 atm on the size, temperature, electron number density, and fraction of laser energy absorbed in a laser-induced plasma in air has been conducted. As pressure is reduced the size of the plasma, its electron number density, its peak emission intensity, and the fraction of incident laser energy that is absorbed are all found to decrease significantly. The temporal temperature profile in the plasma and the fraction of the absorbed laser energy that is converted to thermal energy in the plasma remain constant, at least down to 0.2 atm.