The Plasma Filled Rod Pinch (PFRP) is a radiographic source used in high power flash x-ray machines. The purpose of this study is to provide detailed measurements of the plasma pre-fill required in the PFRP; then use these as a basis for 3D MHD simulations of the dynamics of the plasma in the PFRP.
Several interferometry systems were developed to analyse the density of the plasma pre-fill - a fibre optic based interferometer gave information at a single point over time and a CW laser-based system giving 12 temporally and spatially resolved interferograms. Thomson scattering and spectroscopic analysis were also undertaken, enabling estimates of the electron density of the plasma in the order of 1018 /cm2 at the source with a divergence of 25 - 30°. The velocity of the plasma expansion was found to vary with the charging voltage for the system, with velocities of 8,500 – 14,500 m/s. The 12 frame interferometry system was then used to study the plasma from 6 guns placed around a central rod, a similar orientation to that used in PFRP experiments. The plasma guns were subsequently modelled as simple plasma sources, and the parameters of the plasma were set so that its behaviour matches the experimental data. The model has been used to simulate possible scenarios that could affect the performance of the PFRP.
This study has provided suggestions that the snowplough phase is very resilient to variations away from the standard configuration. Future work will hopefully include simulations featuring the Hall term.