UKAEA Papers

Showing 1491 - 1500 of 1892 UKAEA Paper Results
2008

The physics studies of the three “heating” systems that are installed on JET are reviewed. Results from the beginning of JET up to now are presented with some emphasis on the more recent ones. The systems were used not only for heating, where JET has laid the groundwork to qualify them for heating the next generation of machines to ignition, bu…

Published
2008

A self-consistent kinetic model is developed to study the stability of the resistive wall mode in toroidal plasmas. This model is compared with other models based on perturbative approaches. The degree of the kinetic modification to the stability of the mode depends on the plasma configurations. Both stabilizing and destabilizing kinetic effects ar…

Published
2008

A method to determine the poloidal mode number m in a spherical tokamak based on magnetic probe data was developed. Perturbed magnetic fields at Mirnov coils are calculated for distributed helical filamentary currents on rational surfaces assuming the maximum current amplitude, m and n toroidal mode number, and the toroidal location of the filament…

Published
2008

We motivate the need to include collisional dissipation in gyrokinetic turbulence simulations, and constract criteria for a physically vaUd model of such dissipation. A new analytically manageable operator satisfying those criteria is presented and transformed into gyrokinetic variables. The form of conservation laws for collision operators in gyro…

Published
2008

Charge eXchange Recombination Spectroscopy (CXRS) will play a crucial role in the diagnosing of burning plasmas: items like helium ash, transport barriers, impurity content or fuel ratio can all be assessed with CXRS. In fact this is the only direct method to obtain information about the light impurity ions, such as temperature, concentrations and …

Published
2008

Edge Localised Modes (ELMs) are periodic disturbances of the plasma periphery occurring in tokamaks with an H-mode edge transport barrier. As a result, a fraction of the plasma energy present in the confined hot edge plasma is transferred to the open field lines in the divertor region, ultimately appearing at the divertor target plates. These event…

Published
2008

Advance tokamak scenarios are gaining more and more importance in operating tokamaks. These scenarios pose challenging control problems, since they require the simultaneous achievement of ambitious plasma parameters. The inherent coupling among the various variables calls for an integrated approach for the design of the controllers. This paper desc…

Published
2008

A new analytically and numerically manageable model collision operator is developed specifically for turbulence simulations. The like-particle collision operator includes both pitch-angle scattering and energy diffusion and satisfies the physical constraints required for collision operators: it conserves particles, momentum, and energy, obeys Boltz…

Published
2008

The last flux surface can be used to identify the plasma configuration of discharges. For automated recognition of JET configurations, a learning system based on support vector machines has been developed. Each configuration is described by 12 geometrical parameters. A multiclass system has been developed by means of the one-versus-the-rest approac…

Published
2008

Due to high neutron and gamma-ray yields and large size plasmas many future fusion reactor plasma parameters such as fusion power, fusion power density, ion temperature, fuel mixture, fast ion energy and spatial distributions can be well measured by various fusion product diagnostics. Neutron diagnostics provide information on fusion reaction rate,…

Published