Professor Justin Wark

Abstract:

We report on optical ionisation experiments using the 350fs and 12ps beams of the Sprite: KIF laser at the Rutherford Appleton Laboratory producing ultraviolet laser radiation at focused intensities up to 10(18)W/cm(2). The experiments are concerned with determining the electron temperature of optically ionised gases and are motivated by the possibility of developing XUV recombination lasers based on this technique, Thomson scattering and stimulated Raman scattering, from gas densities varying from 10(17) to 10(20) atoms/cm(-3) have been made and compared with modelling calculations of heating. A particular objective is to identify the relative importance of inverse bremsstrahlung absorption and SRS in determining the temperature of the electrons. Results for 350fs and 12ps pulses are compulsed and the importance of using sub-ps, short wavelength lasers to minimise electron temperature is confirmed.