Prof Peter Norreys FInstP;

Abstract:

High power (8 TW), ultra-short (2.4 ps), pulses have been generated using chirped pulse amplification techniques on the VULCAN Nd: glass laser. A novel oscillator was developed as a driver producing ≈ ps pulses at 105 nm. The oscillator output was stretched prior to amplification and compressed at an aperture of 150 mm. The contrast ratio obtained was ≈ 106, which is suitable for laser plasma interaction studies. © 1993.

Abstract:

The photo-pump strengths of both the ((3d4)o(3d6)o)o-(((3d3)3/2(3d6)o)3/2 (5f)5/2)1 and the ((3d4)o(3d6)o)o-(((3d3)5/2(3d6)o)7/2 (5f)5/2)1 transitions in Ni-like Smw+ have been measured to be 2, 0 x 10-4 and 2.4 x 10-4 photons/mode respectively. The implications of the measurement are briefly discussed in a comparison of the merits of automatically line matched photo-pump scheme to those of the collisional excitation Ni-like Sm+34 scheme. © 1993 IOP Publishing Ltd.

Abstract:

The time varying ratio of intensities of resonance lines of H- and He-like ions in laser irradiated cylindrical fibre targets is analysed using a hydro/atomic physics code. Correspondence between the ratio and gain on the Balmer α transition of H-like ions in the adiabatically cooling and recombining plasma is found. The line ratios and absorbed energies corresponding to maximum gains for carbon, oxygen and fluorine plasmas are calculated. A useful diagnostic method is proposed for infering the absorbed energies in the plasmas and for monitoring the production of plasmas which should give maximum gain during adiabatic expansion. © 1993.