Transformational imaging diagnostics for inertial confinement fusion

Lead Research Organisation: University of York
Department Name: Physics

Abstract

While I was studying for my integrated masters in computational physics at Edinburgh university, a friend commented that as physicists we could contribute to the development of fusion energy. As a result, I'm doing a PhD.
In the summer between my 3rd and 4th years at Edinburgh, I had a fantastic time doing an internship at the Diamond Light Source. While there I was exposed to X-ray imaging (not literally), although it wasn't the focus of my project. Then, between my 4th and 5th years, I attended the CCFE Plasma Physics Summer School.
My Senior honours project looked at lithium/sodium superconducting at high pressure, and my masters project was focused on thin layer turbulence.
My current project's title is "Transformational imaging diagnostics for inertial confinement fusion". Inertial confinement fusion involves heating and compressing a small amount of fuel (deuterium and tritium) with lasers until it is dense and hot enough to undergo fusion. The lasers cause the compression by ablating a surface material, which leads to "the rocket effect". As the material ablates off the surface, it causes a compression force (through Newton's laws), using the same idea that explains rocket propulsion.
The maximum density and heat in the core is achieved with symmetric compression, which requires symmetric ablation, which is quite difficult to achieve. This task is made especially difficult as it is hard to image inside the fuel.
Under the supervision of Nigel Woolsey (University of York) and Robbie Scott (STFC-CLF), my project's goal is to develop new imaging techniques (likely involving phase contrast imaging), to aid and improve inertial confinement fusion diagnostics. This will likely involve using computational simulations to test the imaging technique to see if it yields accurate images and useful results.

Planned Impact

Identifying a sustainable energy supply is one of the biggest challenges facing humanity. Fusion energy has great potential to make a major contribution to the baseload supply - it produces no greenhouse gases, has abundant fuel and limited waste. Furthermore, the UK is amongst the world leaders in the endeavour to commercialise fusion, with a rapidly growing fusion technology and physics programme undertaken at UKAEA within the Culham Centre for Fusion Energy (CCFE). With the construction of ITER - the 15Bn Euro international fusion energy research facility - expected to be completed in the middle of the 2020's, we are taking a huge step towards fusion power. ITER is designed to address all the science and many of the technology issues required to inform the design of the first demonstration reactors, called DEMO. It is also providing a vehicle to upskill industry through the multi-million pound high-tech contracts it places, including in the UK.
ITER embodies the magnetic confinement approach to fusion (MCF). An alternative approach is inertial fusion energy (IFE), where small pellets of fuel are compressed and heated to fusion conditions by an intense driver, typically high-power lasers. While ignition was anticipated on the world's most advanced laser fusion facility, NIF (US), it did not happen; the research effort is now focused on understanding why not and the consequences for IFE, as well as alternative IFE schemes to that employed on NIF.

Our CDT is designed to ensure that the UK is well positioned to exploit ITER and next generation laser facilities to maximise their benefit to the UK and indeed international fusion effort. There are a number of beneficiaries to our training programme: (1) CCFE and the national fusion programme will benefit by employing our trained students who will be well- equipped to play leading roles in the international exploitation of ITER and DEMO design; (2) industry will be able to recruit our students, providing companies with fusion experience as part of the evolution necessary to prepare to build the first demonstration power plants; (3) Government will benefit from a cadre of fusion experts to advise on its role in the international fusion programme, as well as to deliver that programme; (4) the UK requires laser plasma physicists to understand why NIF has not achieved ignition and identify a pathway to inertial fusion energy.

As well as these core fusion impacts, there are impacts in related disciplines. (1) Some of our students will be trained in low temperature plasmas, which also have technological applications in a wide range of sectors including advanced manufacturing and spacecraft/satellite propulsion; (2) our training in materials science has close synergies with the advances in the fission programme and so has impacts there; (3) AWE require expertise in materials science and high energy density plasma physics as part of the national security and non-proliferation strategy; (4) the students we train in socio-economic aspects of fusion will be in a position to help guide policy across a range of areas that fusion science and technology touches; (5) those students involved in inertial fusion will be equipped to advance basic science understanding across a range of applications involving extreme states of matter, such as laboratory astrophysics and equations of state at extreme pressures, positioning the UK to win time on the emerging next generation of international laser facilities; (6) our training in advanced instrumentation and control impacts many sectors in industry as well as academia (eg astrophysics); (7) finally, high performance computing underpins much of our plasma and materials science, and our students' skills in advanced software are valued by many companies in sectors such as nuclear, fluid dynamics and finance.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/S022430/1 01/10/2020 31/03/2028
2440167 Studentship EP/S022430/1 01/10/2020 30/09/2024 Iain Freeman