Shock-Augmented Ignition Approach to Laser Inertial Fusion (Plasma Strand Project)

Supervisors: Nigel Woolsey (University of York), Robbie Scott (Central Laster Facility)

Fusion is the process which occurs at the centre of the Sun and is the source of energy that heats and lights the Earth. Laser-fusion is an approach to recreating the fusion process on Earth ultimately to generate heat and electricity. The fusion fuel, deuterium and tritium isotopes of hydrogen, is both abundant (although tritium must be manufactured) and carbon neutral. Last year the National Ignition Facility in the USA, using lasers to quickly compress a deuterium and tritium plasma to exceptionally high pressures, was the first experiment to exceed breakeven. In this experiment, more energy was released than was used to drive it. This scheme, called indirect drive, uses lasers to create an X-ray source which drives a uniform implosion of a near-perfect millimetre-scale spherical shell containing the fusion fuel. This was one of the scientific highlights of 2022.

In this PhD you’ll have the opportunity to study and develop ideas to make laser-fusion experiments more efficient by reducing the size of the laser needed and increasing the fusion energy liberated. The challenge is to balance a number of interrelated and competing physics processes that lead to inefficiencies in an implosion, these inefficiencies often drive instabilities that either remove energy from the drive or spoil the near-perfect symmetry we need. One approach is shock augmented ignition, where lasers compress the fusion fuel at velocities lower than those we typically use. This helps suppress problematic hydrodynamic instabilities. As the imploding fusion fuel approaches peak compression, a rapid rise in laser-power forms a very strong shock. This shock enters the fusion fuel and collides causing temperatures to exceed the thermonuclear threshold. On exceeding this threshold fusion ignition and burn consumes the compressed fuel. However, the laser intensities needed to create this strong shock drive laser- plasma instabilities which scatter laser energy out of the experiment and accelerate electrons to high energy. At this stage, in the shock augment approach, there is a momentary drop of laser intensity timed just prior to launching the strong shock. This reduces the pressure ahead of the laser absorption region enabling a laser to drive a strong shock at lower intensity. Getting this right requires careful and detailed calculations and experiments.

With this project you’ll have the opportunity to develop highly transferable valuable skills in computational and experimental laser-fusion physics. You will be involved in work at the cutting edge of research using advanced computational and experimental techniques. This includes the utilisation of supercomputing and international experimental resources to design, gather and analyse data.

The project will be shared between York and STFC Rutherford Appleton Laboratories (Oxfordshire), and will likely involve stays in the USA of one to several weeks at a time. There will be in-person and Zoom meetings across the UPLiFT collaboration and with our partners in Europe and the USA. You’ll have the opportunity to present your work at national and international conferences.

This project may be compatible with part time study, please contact the project supervisors if you are interested in exploring this.

This project is offered by University of York. For further information please contact Nigel Woolsey (nigel.woolsey@york.ac.uk)

For details on how to apply, please visit: Apply