Role of positive ions on the surface production of negative ions in a fusion plasma reactor type negative ion source—Insights from a 3D Particle-In-Cell Monte Carlo Collisions model

Results from a 3D self-consistent Particle-In-Cell Monte Carlo Collisions (PIC-MCC) model of a high power fusion-type negative ion source are presented for the first time¹. The model is used to characterize the ITER prototype BATMAN ion source developed in IPP-Garching (Germany). The source is a tandem type device with a cylindrical antenna conferring to the background gas (either molecular hydrogen or deuterium) ~100kW of RF power. This produces high density plasmas of the order of 10¹⁸ m^-3. The expansion chamber, which is connected to the ICP discharge, has a larger volume and is magnetized. The magnetic field is generated by permanent magnets (maximum ~75G on the source symmetry axis).