HEAVY-ION BEAM PROBE SYSTEMS FOR TIGHT ASPECT RATIO TOKAMAKS

We discuss the specific features of the application of heavy ion beam probe (HIBP) systems to tight aspect ratio tokamaks. We present and co mpare the HIBP projects for the TUMAN-3, GLOBUS, and COMPASS, where th e inner part of the plasma is not available for regular chord diagnost ics, so the HIBP becomes very desirable. All existing tight aspect rat io facilities and projects have a low (less than 1.9 T) toroidal field that requires a comparatively low beam energy range. The natural elon gation and triangularity in tight aspect ratio tokamaks require an acc urate calculation of the three-dimensional magnetic field for probing optimization. In comparison with traditional tokamaks, the detector gr ids have a wider energy interval. In general, the trajectories and det ector grids for tight aspect ratio tokamaks become similar to the stel larator ones. Traditional and new probing schemes are suggested and di scussed. (C) 1997 American Institute of Physics.