Influence of the electron thermal conductivity on the threshold and dynamics of the breakdown of insulators containing microinclusions

A theoretical investigation is made of the influence of the electron thermal conductivity of an ionized insulator on the characteristics of its optical breakdown initiated by absorbing microinclusions. The breakdown threshold q* is defined as the minimum intensity of laser radiation at which the temperature distribution in the vicinity of an inclusion first becomes unstable. It is shown that allowance for the electron thermal conductivity changes q* relatively little. The dynamics of optical breakdown in time and space is investigated by numerical integration of the appropriate transient equations. The breakdown threshold found by this numerical method agrees with the results of an analytic treatment.