FEMTOSECOND PLASMA IN SOLID TARGETS WITH REDUCED THERMAL CONDUCTION -X-RAY-PRODUCTION AND 2ND-HARMONIC GENERATION

In the present work, it is shown that, by modifying physical propertie s of near-surface layer of the target, one can obtain effective contro l over parameters of femtosecond laser plasma (temperature, ionization degree, radiative capability, nonlinear optical susceptibility) with moderate values for intensity l(1) similar to 10(15)-10(16) W/cm(2)-mo st acceptable from the point of view of the perspective technologies: laser-plasma femtotechnologies. Experimental data is presented for fre ely suspended ultrathin films and porous targets. Considerable X-ray y ield increase into ''water window'' spectral region is detected for ca rbon film target 20-30 nm thick. In the case of porous silica, signifi cant hot electron temperature increase up to 7 keV is observed.