Production of fast ions by the 3wo PALS laser beam

Abstract

The investigations of nonthermal processes in laser-produced plasmas are not yet complete, especially with regard to the ion acceleration in the plasma generated by high-energy short-wavelengths lasers. This contribution presents the results of studies of fast ion emission from plasma generated using a short wavelength (438 nm), high-energy (up to 250 J in 400 p5 pulse) iodine laser PALS at the Joint Research Laboratory PALS ASCR in Prague, Czech Republic. The properties of highly charged ion streams were investigated by ion diagnostic methods: ion collectors and solid state track detectors as well as a cylindrical electrostatic energy analyzer. Attention was paid to the determination of ion energy and comparison of the energies and abundance of different ion groups. The presented results shown the existence of highly charged ions with z <40 (measured z, =57 forTa) and with energies higher then 20 MeV in a far expansion zone. Ion current densities up to tens of mA/cm2 at a distance of 1 m from the target were obtained. On the basis of the ion diagnostic investigations the existence of nonthermal and nonlinear accelerating processes was demonstrated for the plasma produced by a high-energy short-wavelength laser pulse.