Using multi-spectral imaging and advanced data analysis to improve the tokamak fusion concept.

I studied for both my undergraduate and master degrees in Physics at the University of Padua, in Italy. My interest in nuclear fusion started during my bachelor thesis research on developing a convolutional neural network for the analysis of infrared imaging system data on the SPIDER experiment. It then continued during my masters degree through elective courses and it culminated in my masters thesis on the study of parametric decay instabilities during Electron Cyclotron Resonance (ECR) heating on the NORTH tokamak at the Technical University of Denmark.

My PhD project, supervised by Prof. Bruce Lipschultz and Prof. Kieran Gibson at the University of York and Dr. James Harrison at CCFE, involves the study of the divertor region of the MAST-U tokamak through the new Multi Wavelength-Imaging (MWI) diagnostic.

This diagnostic allows researchers to acquire eleven video movies corresponding to 2D brightness images of the divertor region, each filtered for a different wavelength. The profiles have different dependencies on the plasma parameters and by putting them together with the data from the other diagnostics, these parameters can be reconstructed. The MWI data will be integrated in the Bayesian framework currently being used to determine the divertor state, thereby improving its capability.

Handling the large exhaust heat loads corresponding to that of a reactor is one of the main problems on the way to commercial fusion tokamaks providing a net power source. The magnetic topology of the divertor (where the exhaust power is carried towards surfaces) in MAST-U is flexible and the MWI diagnostic will help in determining the most appropriate divertor configuration to optimize the dissipation of power and thus reduce peak power loads.

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.