The heating of the titanium foil in a recent femtosecond laser plasma experiment is investigated theoretically in two different ways. In the first, the energy content and thus the heating efficiency of the central volume of the foil is derived by integrating the transverse temperature profiles obtained in this experiment, using specific heats based on the average atom model. In the second approach target heating by the fast electrons, both by direct energy deposition and by resistive heating is investigated. The latter approach makes use of a specially devised electron flow model which includes a simplified quantitative treatment of multi-refluxing as a crucial component. In all, the calculated results of electron beam heating are consistent with experiment within the limitations of the modeling. Finally, a prediction for the temporal dependence of the Kα pulse from the central volume of the foil based on our electron flow model is given.

Recent results on constructing of an efficient hard X-ray source using solid targets irradiated by high-contrast 200-fs laser pulses with an intensity above 1016 W/cm2 are presented. We used different solid targets with a laser- and electrochemically modified surface layer: craters, pyramidal cavities, porous silicon, gratings. Experimental data obtained confirms that using solid targets with a corrugated surface one can achieve a prominent increase both in the efficiency of hard X-ray generation (in the quanta range 2–30 keV) and in the hot electron temperature of plasma.