The results of the experiments at the installation
“PICO,” with thin foils heating by laser radiation
pulses of nanosecond duration are reported. The Al foils
with thickness in the range from 3 μ up to 40 μ
were used as targets. The flux density was varied from
1013 W/cm2 to 1014 W/cm2.
The sharp dependence of the portion of laser energy that
passed through the target on foil thickness was observed.
This phenomena was accompanied by a relatively small decrease
of the passed radiation pulse duration. The anomalously
high speed burning through of thin foil was observed in
these experiments and the conclusion on the possible mechanism
of this phenomena has been done on the base of comparison
of experimental data with theoretical calculations. The
observed phenomena can be interpreted with a conjecture
about the local burning through of a target, in the small
areas of the target surface, with many more values of flux
density than the average one following laser radiation
self-focusing and formation of “hot spots.”