Characterising Plasma Ions in the MAST-U Divertor (plasma strand project)

Supervisors: Professor James Bradley (University of Liverpool) and Dr James Harrison (CCFE)

The energy and species composition of plasma ions near material surfaces in tokamak divertors strongly governs the plasma-material interactions, e.g. sputtering from divertor surfaces and recycling behaviour. This project is concerned with determining the ion energy spectrum and species composition of the plasma in the new closed MAST-U using a Retarding Field Energy Analyser (RFEA), originally used on MAST, initially to explore the role of the new baffling structures on the ions reaching divertor surfaces. In parallel, a Plasma Ion Mass Spectrometer would be developed for use on MAST-U, to measure the mass spectrum of the plasma. These measurements are very useful in themselves to ascertain the impurity content of the plasma in the divertor in attached and detached conditions, but also informs the interpretation of data from RFEAs, which are sensitive to both bulk ions and impurities.

The project will be based mostly at CCFE (Culham), but with the opportunity to carry out some experimental and design studies at the University of Liverpool through a number of short term visits. The project will also offer the chance for overseas travel for conferences and meetings, particularly to other international fusion experiments involved in ion energy measurements and ion mass (impurity) spectrometry.

The project involves diagnostic hardware design and implementation as well as data interpretation and any associated programming.

This project is offered by University of Liverpool. For further information please contact: Professor James Bradley (J.W.Bradley@liverpool.ac.uk)