Some features of the behavior of an intense light beam in a nonideal gas

It is shown that deformation of a medium by a strong inhomogeneous electromagnetic field does not alter the enthalpy of the medium. It follows that there are inversion temperatures analogous to the inversion points in the conventional Joule–Thomson effect. The existence of such inversion temperatures may affect self-focusing of light beams: It may reduce the self-focusing threshold and length, depending on the initial temperature of the medium.