Resonant coupling between surface and interface plasma waves in high-density sharp-edged planar or spherical plasmas produced by ultrafast laser pulses

We consider the interaction between an ultrashort laser pulse a hot high-density sharp-edged laser-created plasma resulting either from a micro-structured target (planar geometry) or from a granular one with a double-step density profile. We demonstrate that an electron plasma wave can be resonantly driven at the density jump between the two plasmas by the field of a laser-excited surface wave leading to additional light absorption. Different excitation regimes are studied depending on the wavelength and the geometry of the plasma. Particular attention is paid to nonlinear regimes owing to the possibility of energetic electron generation and Kα X-radiation emission. (authors)