Research

Theory and modelling

Computer image of MAST dataThe purpose of this programme is to use analytic theory and sophisticated computer codes to support the tokamak experiments, and to make reliable predictions of the performance of future fusion devices, such as ITER, a spherical tokamak Component Test Facility and a demonstration power station. The models developed are tested where possible by comparisons with data from MAST, JET and other tokamaks. Parallel computing facilities at Culham Centre for Fusion Energy, EPSRC and European supercomputers are used for some simulations, many of which are undertaken in collaboration with universities and with other Fusion Associations as part of EFDA's Integrated Tokamak Modelling Task Force.

The CCFE theory and modelling programme covers many of the key topics in fusion plasma physics:

Confinement

Losses of energy and particles from the plasma must be kept to a minimum for an effective system – the confinement efficiency determines how large a system needs to be to produce more energy from fusion than is needed to keep the plasma hot.

Plasma instabilities

When the plasma current, pressure or density are raised too high the plasma can become unstable. Unless mitigating action is taken, plasma performance is degraded or control of the plasma is lost and plasma-facing equipment can be damaged.

Plasma exhaust

The edge of the plasma must be sufficiently cool where it meets material surfaces to ensure that damage to these surfaces and pollution of the plasma by impurities is minimal. Very high transient heat loads must also be avoided.

Steady-state operation

Ideally, a fusion power station would operate continuously (in ‘steady-state') to avoid cyclic stresses and large energy storage systems. Research is conducted into advanced tokamak operating modes which might allow this.

Optimum configuration

The JET/ITER-like tokamak is the most developed system, though other magnetic configurations have advantages, including the spherical tokamak developed at Culham.