Overheated plasma at the surface of a target with a periodic structure induced by femtosecond laser radiation

A periodic structure is induced at the surface of a metal target exposed to a series of $p$-polarized 200-femtosecond laser pulses with intensity close to the melting threshold of the target material. The period of the structure is determined by the interference between the incident pump wave and the surface electromagnetic wave. Exposure of the obtained structure to the same laser pulse, but with an intensity of $\sim10^{16}\,$W/cm$^2$, provides resonant excitation of the surface electromagnetic waves at the plasma-vacuum interface. This leads to an increase in the X-ray output and the temperature of plasma hot electrons.