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.