Atomic and molecular processes in ion source plasmas

In the hydrogen negative ion sources applied to fusion plasma heating, large proton accelerators, boron neutron capture therapy equipment, etc., the plasma parameters are close to those of fusion diverter plasma, and the atomic/molecular processes such as ionization and dissociation are similar. From this reason, the collision radiation model of hydrogen atoms/molecules and the neutral particle transport code cultivated in the modeling of plasmas around nuclear fusion are frequently utilized. In the neutral particle simulation model of ion sources explained in this paper, the model expansion which adopted the volume formation process and surface generation process of negative ions characteristic to negative ion sources, as well as the effects of transport and non-equilibrium energy distribution in the electromagnetic field that affect these processes has been promoted in recent years (about 15 years). In addition, by developing a model that reproduces the ion source spectroscopic measurement results, it has become possible to provide ion source design guidelines from the simulations. (A.O.)