Review of laser ion sources developments in Prague and production of q over 50+ ions at Prague Asterix Laser System (invited)

Abstract

The high-power iodine laser systems PERUN and Prague Asterix Laser System, with a maximum attainable laser intensity IL of up to about 6×1016 W/cm2, were used to generate highly charged ions of various elements (Al,Co,Ni,Cu,Ag,Sn,Ta,W,Pt,Au,Pb,Bi). The properties of ions were investigated mainly on the basis of time-of-flight method using ion collectors, cylindrical electrostatic ion energy analyzer, Thomson parabola spectrometer, and track detectors. Simultaneous x-ray and interferometric measurements were also implemented. Maximum ion charge states of heavy ions above z=50+ were recorded and the maximum energy of emitted ions exceeded Ei=22 MeV. Using laser intensities of about 1×1016 W/cm2 can produce such ions. Due to the convenient pulse length of the iodine laser, part of the pulse may interact with the self-created expanding plasma. It was proved that in this case the conditions for an appearance of the relativistic self focusing may be fulfilled (position of minimum focus spot in front of the target surface and the threshold laser intensity about 3×1014 W/cm2) and the highest charge states above 50+ may be generated, too.