Optimized heavy ion beam probing for International Thermonuclear Experimental Reactor

The international workgroup developed the conceptual design of a heavy ion beam probe (HIBP) diagnostics for International Thermonuclear Experimental Reactor (ITER), which is intended for measurements of the plasma potential profile in a gradient area. Now we optimized it by the accurate analysis of the probing trajectories and variation of positions of the injection and d etection points. Optimization allows us to reduce the energy of Tl+ beam fr om 5.6 to 3.4 MeV for standard ITER regime. The detector line starting at t he plasma edge towards the center can get an outer part of the horizontal r adial potential profile by variation of the energy. The observed radial int erval is slightly increased up to 0.76<rho<1 with respect to initial versio n 0.8<rho<1, that allows to cover the region of the density gradient more r eliably. Almost double reduction of the beam energy is a critical point. Th us we can significantly decrease the sizes of the accelerator and energy an alyzer, the cost of the equipment, and impact of the diagnostics to the mac hine. Therefore the optimized HIBP design can be realized in ITER. (C) 1999 American Institute of Physics. [S0034-6748(99)75201-9].