Studies of high temperature laboratory and astrophysical plasmas

Presented in this thesis are numerical simulations from the code GALAXY, frequently employed to model the distribution of excitation and ionization from laboratory plasma experiments. The benchmarking photoionization experiments on theZ-machine at the Lawrence Livermore National Laboratory are described, and results from these are used to show the accuracy of the simulations performed by GALAXY and possible areas for improvement in the calculations. The expected impact of the benchmarking of photoionization codes with Z-pinch data will be the more reliable interpretation of past, present and future X-ray astronomy data. Also presented here are calculations carried out to determine the densities of solar flares and active regions observed using the Solar Maximum Mission (SMM) satellite. Analysing the helium-like ion Mg XI and the nearby lithium-like Mg X, it is found that about 30% of the events observed had high electron densities, i.e. above 10"1"2 cm"-"3. Finally, a project is described that proposes an alternative use for the VULCAN laser at the Rutherford Appleton Laboratory. It is suggested that, instead of its obvious uses in plasma production, the laser could be directed toward possible planets around nearby Sun-like stars. It is shown to be possible, but not practical with current ground-based lasers. (author)Available from British Library Document Supply Centre- DSC:DXN060106 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo