Numerical analysis of surface produced H^- ions by using two-dimensional particle-in-cell method

The modeling and analysis of a negative ion source is proceeding by using a 2D particle-in-cell simulation. The effect of the H^- ion production on the plasma grid (PG) surface is investigated. It is shown that with the increase of H^- ions per time step, the H^- ion current density is enhanced, while the electron current density decreases with increasing the H^- production rate on the PG surface. These results agree well with the experimental results observed in typical negative ion sources. Moreover, it is found that plasma quasi-neutrality is held mainly by both H⁺ and H^- ions in the bulk plasma around the PG.