Speaker
Description
The multi-cusp magnetic field is widely used to improve plasma confinement in high-current negative ion sources for neutral beam injection (NBI) systems in fusion devices. Since confinement performance is affected by the plasma potential and magnetized sheath structure, understanding potential formation and particle loss processes in cusp magnetic fields is important. However, these mechanisms are not yet fully understood, especially in negative ion sources.
In this study, a two-dimensional Particle-in-Cell (PIC) simulation was carried out to investigate sheath formation and wall-loss distributions in a cusp magnetic field configuration. In simulations including positive ions and electrons, the sheath potential normalized by the plasma temperature increased as the plasma temperature increased. This trend is mainly attributed to the increase in the electron Larmor radius, which weakens electron confinement and increases electron loss to the wall. Characteristic wall-loss distributions caused by the cusp magnetic field structure were also observed. The effects of negative hydrogen ions on sheath formation and particle loss processes are also discussed.
| Email address | tetsu3328194771@keio.jp |
|---|---|
| Visitor's Visa | no |
| Classification | Numerical simulations of sources, beams, space-charge, ion-optics |