A STUDY OF PICOSECOND LASER-SOLID INTERACTIONS UP TO 10(19) W CM(-2)

The interaction of a 1053 nm picosecond laser pulse with a solid targe t has been studied for focused intensities of up to 10(19) W cm(-2). T he maximum ion energy cutoff E(max) (which is related to the hot elect ron temperature) is in the range 1.0-12.0 MeV and is shown to scale as E(max) approximate to I-1/3. The hot electron temperatures were in th e range 70-400 keV for intensities up to 5X10(18) W cm(-2) with an ind ication of a high absorption of laser energy. Measurements of x-ray/ga mma-ray bremsstrahlung emission suggest the existence of at least two electron temperatures. Collimation of the plasma flow has been observe d by optical probing techniques. (C) 1997 American Institute of Physic s.