PhD opportunities

Absorption physics of intense twisted light with solid targets


Supervisor Dr Robert Kingham
Type Computational & Theoretical
Funding DTA (group or Dept/Faculty)
Info

This project will explore how intense, picosecond-duration laser beams possessing orbital-angular momentum (OAM) interact with solid density plasma. Laser beams with OAM have ‘spiral’ phase-fronts (hence the term ‘twisted’ light) and each photon carries ±ℏ of angular momentum.  Such beams, and their interaction with matter, are well understood in conventional optics, where the intensity is low.  However, the study of what happens at the ultra-high, “relativistic” laser intensities ( I ≥ 1022 W/m2 ) used in laser-plasma interactions is still in its infancy. Most research focuses on the interaction of OAM pulses with under-dense plasma. This project will focus on their interaction with solid-density plasma. The idea is to explore how angular momentum in the laser affects the laser absorption efficiency, the characteristics of the energized electrons and magnetic-field generation.  These are fundamental processes that underpin a range of applications such as proton acceleration and advanced ICF schemes.  The investigation would be carried out using a combination of HPC simulations (using the particle-in-cell code EPOCH) and analytical theory. There may be opportunities to engage with experiments.

Rad-hydro modelling of hohlraum energetics including VFP electron transport


Supervisor Dr Robert Kingham 
Type Computational & Theoretical
Funding CIFS (otherwise DTA)
Info

The goal is to improve the treatment of electron thermal transport under the extremely non-equilibrium conditions found in indirect-drive ICF.  This could help understand the origins of the ~25% X-ray ‘drive deficit’ between experiment and modelling, seen at the National Ignition Facility in the US. This will be achieved by coupling an existing 2-D kinetic code for electrons (a Vlasov-Fokker-Planck code) to a radiation-hydrocode. The coupled code will allow  –  for the first time  –  proper assessment of the role of non-local effects and kinetic B-field dynamics in an integrated way on the hohlraum gas-fill, ablated wall plasma, and x-ray source at the wall in 1D and then 2D. The methodology to be developed here should also be applicable to aspects direct-drive ICF, and there may be opportunities to explore this too.  This project will involve close collaboration with LLNL.