Microwave heating & current drive on the MAST Upgrade Tokamak (plasma strand project)

Supervisor/s – Roddy Vann (University of York). Simon Freethy (UKAEA) and Alf Köhn (University of Stuttgart).

Microwaves are the part of the electromagnetic spectrum with wavelengths approximately ranging from a few centimetres to a millimetre. Microwaves find a range of applications in tokamaks: diagnostics (measuring, for example, temperature, density, magnetic pitch angle, turbulence) and, at high power, heating and driving current in the tokamak plasma. Spherical tokamaks, pioneered in the UK, have a much smaller aspect ratio than conventional tokamaks – i.e. their shape is more similar to a cored apple than a bicycle tyre. In these devices, the magnetic field strength is relatively low and the density is relatively high which means (long story!) that conventional microwave current drive (known as electron cyclotron current drive (ECCD)) can’t be used. It has been proposed instead that microwaves can generate current via a rather exotic family of waves called electron Bernstein waves (EBWs).

Consequently UKAEA is currently designing and installing a multi-megawatt microwave system for MAST Upgrade to improve the scientific basis for EBW current drive in a reactor environment. The aim of this PhD project is to design and execute experiments that measure the current drive efficiency of EBWs over a range of plasmas, fully quantifying the uncertainties of the measurements and comparing to model predictions. The experimental planning will be undertaken with the help of existing EBW ray-tracing and Fokker Planck codes, as well as integrated modelling tools.

The project will be based in York for the first 9-12 months but thereafter will involve a placement of at least 12 months at the Culham Centre for Fusion Energy in Oxfordshire.

This project is offered by The University of York. For further information please contact: Roddy Vann (roddy.vann@york.ac.uk)

This project may be compatible with part time study, please contact the project supervisors if you are interested in exploring this.