Thermal analysis of beamline heat load components due to increased power delivery from EAST neutral beam injector

According to EAST’s experimental plan, the long-pulse and high-power operation of neutral beam injector is the requirement for EAST. In this paper, the operation range of beam perveance is adjusted from 1.9–2.5 μP to 2.5–3.3 μP through changing the voltage ratio of gradient grid/plasma grid from 0.84 to 0.78. The thermal analysis of beamline heat load components shows that with the decrease in the voltage ratio of gradient grid/plasma grid from 0.84 to 0.78, the maximum neutral beam power deposition on the calorimeter increases from 825 to 950 kW when accelerating voltage is 50 kV. The results show that the minimum beam divergence increases from 1.25° to 1.32° and the maximum temperature rise of bending magnet collimator increases from 10 to 27 °C. The results in this paper are helpful to find a balance between increase in power delivery capability and prolongation of beam extraction duration and lay a basis for achieving plasma heating according to the physical experimental requirement of EAST.