Abstract:
The interaction of femtosecond laser pulses with SiO$_2$ aerogel targets has been analyzed by x-ray spectroscopic methods. The use of an aerogel target with transparent grains makes it possible to considerably reduce the requirements on laser-pulse contrasts for which heating occurs without the formation of a preplasma. A nanoplasma with a density sevenfold higher than the solid-state density has been detected.