Short-pulsed laser-induced breakdown in dielectrics with strong electron superheating: diffusion-controlled kinetics of impact ionization and recombination

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In this work we model the diffusion-controlled kinetic mechanisms of (i) the strong electron superheating above the critical energy of impact ionization that develops within the generated skin depth when the neutral atoms deplete and (ii) recombination effects, which are involved in short-pulsed laser-induced breakdown and after-pulse relaxation in dielectrics. In the numerical simulations we use (iii) the two-temperature model modified for laser-matter interaction with dielectrics in combination with (iv) a computational approach developed for treating the auto-oscillatory dynamics of the electron energy and density induced by the onset of impact ionization during pulsed laser excitation and after-pulse relaxation.