Oxford Centre for High Energy Density Science (OxCHEDS)

Abstract:

In recent experiments the capacity has been developed to generate plasmas at high densities. Standard methods used to diagnose plasmas are difficult to apply at these conditions, since it is necessary to calculate the entire spectrum as there is significant overlap of spectral lines. However, for most elements, the number of individual spectral line profiles calculated using the semiclassical method is very small. We present a method to use an approximate line width formula, coupled with an accurate database to generate a large number of line profiles. We evaluate the accuracy and utility of such an approach by comparison with semiclassical calculations. © 1997 The American Physical Society.

Abstract:

We describe experiments that demonstrate the detrimental effect of a prepulse on the femtosecond-pulse-driven Xe IX laser. The mechanism of this effect is discussed in terms of the results of a hydrodynamic model of the preplasma formed by the prepulse. The benefit of inserting a simple electro-optic switch that allows full transmission of the main driving pulse, but reduces the prepulse to a level at which no preplasma is formed, is demonstrated experimentally. © 1997 Optical Society of America.

Abstract:

Hooker explores current work in the XUV and soft x-ray spectral region aimed at achieving "table-top" short-wavelength lasers.

Abstract:

Titania is the latest series of ultraviolet laser systems developed with the highest laser beam brightness. It can be configured in two alternative modes which can deliver a brightness of <1020 W cm-2 sterad-1. The first mode, used a chirped pulse amplification (CPA) to produce the shortest possible pulses. Values of 300 fs on the target are measured. The energy limitations of the CPA scheme are removed in the alternative architecture based on Raman beam combining. The Titania Raman system is designed to operate optimally with pulses of 30-500 ps duration.