Effects of Hydrogen Negative Ions on Plasma with Magnetic Field Decreasing toward a Wall

Effects of H- ion on distributions of electric potential and plasma density near the wall with the magnetic field decreasing toward the wall are investigated analytically. In the analysis, the magnetic field is assumed to be perpendicular to the wall, and the problem is treated as one-dimensional model. The plasma-sheath equation is derived analytically and the potential distribution near the wall is obtained by solving the plasma-sheath equation. The plasma density distributions are obtained from the potential distribution. It is shown that the effect of the production amount of H - ion on plasma density distributions is large. The effect of the magnetic field profile and the ion temperature on the distributions of electric potential and particle density are also shown. (C) 2018 The Japan Society of Plasma Science and Nuclear Fusion Research