Abstract:
The plasma formation thresholds were determined for metal (Al, Cu) and dielectric (K8 glass, KV quartz) targets irradiated with laser pulses (λ = 1.06 μm, τ = 10–12 and ~10–10 s). It was found that the lowest surface energy density ε* needed to form a plasma decreased by two orders of magnitude, compared with the case of interaction of radiation characterised by the parameters λ = 10.6 μm and τ ~10–6 s. An analysis of the results indicated that the ‘short’ thermal model of plasma initiation remains valid in the τ ~10–12 — 10–10 s range of durations.