Magnetic Confinement Fusion

In magnetic confinement fusion (MCF), the fuel (deuterium and tritium) is heated to a temperature which is ten times that at the centre of the Sun. It is then an ionised gas: a state of matter referred to as a plasma. We confine this plasma, holding it away from material surfaces (which would otherwise suffer serious damage) by a combination of magnetic fields in a toroidal (doughnut-shaped) geometry. The device we are particularly interested in, and that which shows most promise for fusion, is the tokamak.

Three of the plasma group's staff are engaged full-time on magnetic confinement fusion research: two with theory expertise and one experimentalist. Other academic staff whose main interest is laser-plasma interactions, also play an active role in the experimental MCF research, exploiting the significant overlap in experimental techniques to diagnose plasma properties. The group has two post-docs working on theoretical problems (one of whom also has significant experimental experience). There are twelve post-graduate students engaged in both theoretical and experimental research programmes.

Our research, which is funded mainly through EPSRC, is strongly linked to the UK's national fusion research programme at the Culham Centre for Fusion Energy (CCFE) and, indeed, several of our PhD students are based at Culham Science Centre. We place a particular emphasis on topics which are both relevant for fusion energy production and involve interesting, novel basic plasma science. In particular, our work is very much focussed on the key issues that need to be addressed for the international ITER tokamak, presently under construction in the South of France and due for completion around 2016.

Our research involves the full range of physics disciplines:

  • We develop analytic theories for a range of plasma instabilities.
  • We employ existing large scale computer codes and build new ones to study plasma turbulence, stability and eruptions (so-called edge-localised modes, or ELMs). Here we make use of the EPSRC's high performance computer HECToR, as well as a smaller scale Beowulf cluster that we have in the Physics Department.
  • We perform experiments on the major tokamaks at Culham Science Centre in Oxfordshire: the spherical tokamak, MAST, and the World's largest tokamak, JET. These are mainly focussed on the properties of the plasma, such as stability and transport, but we are also involved in plasma-wall interaction studies and material issues such as tritium retention.
  • We design and help build and install a number of plasma diagnostic tools. A major collaborative project with CCFE is the £2M upgrade to the MAST Thompson Scattering system, which will be completed in 2009. We are also involved in experiments using a range of spectroscopic, Langmuir probe and magnetic diagnostics on MAST. We have access to MAST data via a dedicated "MAST remote control room" at York, which provides a range of data analysis and visualisation tools (see image below)

Dr Roddy Vann in the MAST 'remote control room' facility at York.
Dr Roddy Vann in the MAST 'remote control room' facility at York.

In addition to research, we are also actively engaged in a number of outreach activities, such as giving lectures on fusion to the general public and schools. In 2007, we worked with Culham to host a Fusion Expo here in York as part of the British Association for the Advancement of Science Festival of Science.

Dr Ben Dudson preparing a model coil for a stellarator exhibit for the EU Fusion Expo for the BA Festival of Science in York, 2007. (Can you spot the deliberate mistake?)
Dr Ben Dudson preparing a model coil for a stellarator exhibit for the EU Fusion Expo for the BA Festival of Science in York, 2007 (can you spot the deliberate mistake?)

 
The MAST spherical tokamak at Culham Science Centre.