James Clark

University Of Liverpool

I am a CDT student under the joint supervision of Dr Mark Bowden at the University of Liverpool and Dr Rory Scannell at the Culham Centre for Fusion Energy (CCFE). Based down at CCFE I am working on low temperature Thomson scattering on MAST-U.

Thomson scattering is a diagnostic technique that has been used in fusion grade plasmas around the world for many years. It is used to measure the electron temperature and density during an experiment. High powered laser light is fired into a targeted region of the plasma and the scattered light returned allows these characteristics to be determined. A number of these systems will be in place on MAST-U, all of which are based around the core system which is used to measure electron properties across the bulk of the high temperature plasma.

The MAST-U Super-X divertor is one of the key points of MAST-Upgrade where the heat from the core of the reactor is exhausted. Thomson scattering systems in this region of a fusion reactor are very uncommon. As a part of the upgrade two new TS systems are being developed. One of these is for the divertor itself and the other for the x-point, the region where the core plasma transitions into the divertor. These new systems present additional challenges due to the complex geometry of the divertor region and the rapidly changing plasma conditions, particularly the lower electron temperatures.

During my project I will be working with both of these low temperature Thomson scattering systems. With the divertor system I will be part of a team taking it from its first experimental operations to a routine diagnostic that operates for all experiments. The x-point system is currently still under development and I will have the opportunity to influence the design and implementation of the system, potentially obtaining the first results.