Oxford Centre for High Energy Density Science (OxCHEDS)

Abstract:

We present molecular dynamics simulations of shock and release in micron-scale tantalum crystals that exhibit postbreakout temperatures far exceeding those expected under the standard assumption of isentropic release. We show via an energy-budget analysis that this is due to plastic-work heating from material strength that largely counters thermoelastic cooling. The simulations are corroborated by experiments where the release temperatures of laser-shocked tantalum foils are deduced from their thermal strains via in situ x-ray diffraction and are found to be close to those behind the shock.

Abstract:

The EuPRAXIA project aims at designing the world's first accelerator based on advanced plasma-wakefield techniques to deliver 5 GeV electron beams that simultaneously have high charge, low emittance and low energy spread, which are required for applications by future user communities. Meeting this challenging objective will only be possible through dedicated effort. Many injection/acceleration schemes and techniques have been explored by means of thorough simulations in more than ten European research institutes. This enables selection of the most appropriate methods for solving each particular problem. The specific challenge of generating, extracting and transporting high charge beams, while maintaining the high quality needed for user applications, are being tackled using innovative approaches. This article highlights preliminary results obtained by the EuPRAXIA collaboration, which also exhibit the required laser and plasma parameters.