Laser Plasma Accelerators (JAI)

PhD Project for October 2026
Supervised by Professor Zulfikar Najmudin, z.najmudin@imperial.ac.uk
Type - Experimental (but will include simulation work)

Recent advances in inertial confinement fusion have recently measured energy output greater than the mechanical energy put into the compression of a DT capsule finally demonstrating the laser-driven ignition of a fusion pellet [1] [2]. These exciting results suggest that we are at the dawn of being able to control fusion in the laboratory, and potentially opening this up as a new source of (carbon-free) energy. These results were made possible by continuing improvements in capsule design and better understanding of the power balance between laser beams to ensure more uniform irradiation of the capsule being compressed. However, the results to-date still suffer from shot-to-shot fluctuation, with only one shot providing an energy yield well in excess of the energy given to the capsule. Most of the difficulties in the compression have been a result of lower-than-expected velocities for the laser-driven shocks that initiate the compression, which has only been inferred the poor neutron yields in previous shots. Being able to diagnose and characterise the shock formation and velocity would be a major step in better controlling the inertial confinement process.

We have been developing new x-ray imaging techniques for characterising dense matter interaction with high temporal and spatial resolutions. This source is based on synchrotron radiation from laser wakefield accelerators. The same large fields that make wakefield accelerators much more compact than conventional accelerators, also make them emit synchrotron radiation strongly. The source, with its small temporal and spatial emission size, and high photon energy (> 10 keV) is ideal for diagnosing dense dynamic systems [3]. We propose to use this imaging source to better understand the coupling of laser energy to a variety of targets in direct-laser driven targets as would be found in ICF experiments. We also attempt to observe and optimise the shock formation depending on different laser smoothing techniques used to give a more uniform illumination of the targets.