Conceptual design of a heavy ion beam probe diagnostic for HL-2M tokamak

Abstract

The conceptual design of a heavy ion beam probe (HIBP) for HL-2M tokamak has been proposed to measure the plasma potential, electron density and their fluctuations to contribute to the understanding of advanced confinement modes and transport. Beam trajectory calculations are performed under 3D magnetic field and engineering conditions of the facility. By choosing the positions and angles of both primary and secondary beamlines, a wide region of observation area (0.1<r/a<0.9) is achieved with 2 MeV Tl+ beam injection. The active trajectory control technique is used to obtain the poloidal sweep angle between −10∘ and 10∘. Then, the applied voltages of sweep plates are evaluated to be up to 25 kV. By integrating ionization and attenuation along beam paths, the detected signal level distribution in the plasma density condition n0=5×1019m−3 is higher than 100 nA with 100μA injection beam intensity in most of the plasma region, which ensures an acceptable signal-to-noise ratio for measurements.