Hard x-ray and high-energy protons production under femtosecond laser interaction with free liquid surface

摘要

It was demonstrated experimentally that liquid with low pressure of saturated vapor can be used as target for femtosecond laser plasma formation. Plasma formed at free liquid surface (vacuum oil) in vacuum by femtosecond laser pulse with intensity above 10~(16)W/cm~2 is similar to high-temperature plasma formed at solid target surface. So, from x-ray and ionic time-of-flight measurements the temperature of hot electrons for oil target is 6+-3keV and for crystalline silicon target is 4+-lkeV. The optics diagnostic of liquid surface relaxation has shown that upper repetition rate of laser pulses for interaction with non-perturbed liquid surface is 10Hz.