Electromagnetic gyrokinetic-ion drift-fluid-electron hybrid simulation

Progress on gyrokinetic-ion drift-fluid-electron hybrid simulation is repor ted. Simulation results are shown from a three-dimensional toroidal electro magnetic simulation using held-line-following coordinates. It is found that for beta greater than or similar to 1.5% there is strong destabilization o f Alfvenic ion-temperature-gradient (ITG) driven instabilities. Nonlinear r esults show a corresponding increase in the the ion heat flux. Secondly, we report very good parallel performance and near perfect scalability was sho wn on the Gray T3E and SGI O2K using a one-dimensional domain decomposition and digital filtering to handle the shift at the boundary along the magnet ic field-line due to toroidal boundary conditions. Finally, we report recen t results in the electrostatic limit, which explore: a scheme to reduce the heat flux by adding a ripple to the ion temperature profile. Both self-gen erated and equilibrium E-r shear flows are included for the first time. It may be possible to achieve similar results experimentally using ion cyclotr on resonance beating. (C) 2000 Elsevier Science B.V. All rights reserved.