Electron gas compression and Coulomb explosion in the surface layer of a conductor heated by femtosecond laser pulse

The hypothesis is put forward on the basis of experimental data that strong inhomogeneous heating of the skin layer of conducting materials by a femtosecond pulse gives rise to a double electrical layer that is formed of a “surface” layer of positive ions and a thin (about 1 nm) “subsurface” layer of a superdense (10 23 –10 25 cm −3 ) degenerate electron gas. The double layer breaks within one picosecond through the Coulomb explosion.