Congratulations to Joe Allan, a York Fusion CDT student who successfully defended his thesis at viva in June 2021. Joe’s thesis is entitled “Design of the Synthetic Aperture Microwave Imager-2 for measurement of the edge current density on MAST-U” and his supervisor was Professor Roddy Vann.

An abstract from Joe’s thesis is below. Joe is now working for UKAEA in the team designing an electron Bernstein wave heating system for MAST-U.

Well done Joe!

“The Synthetic Aperture Microwave Imager-2 (SAMI-2) is a 2D Doppler backscattering (DBS) diagnostic designed for multiple high quality simultaneous measurements of the edge pitch angle on the Mega-Ampere Spherical Tokamak Upgrade (MAST-U). The specification, design and testing of the SAMI2 microwave front end, predominantly antennas and mixer circuitry, are described in this thesis. A radial profile of the edge pitch angle enables calculation of the edge current density, a difficult quantity to measure, which is valuable for validation of models and understanding of pedestal dynamics and edge plasma instabilities, e.g. ELMs. In active probing mode, the SAMI-2 diagnostic is designed to make the first measurements of the edge current density by a DBS diagnostic. In passive mode, SAMI-2 will measure Bernstein wave mode conversion, to inform spherical tokamak microwave heating systems”.