Three-dimensional effect of particle motion on plasma filament dynamics

It is shown for the first time with the three-dimensional (3D) electrostatic particle-in-cell simulation that the plasma particle motion influences plasma filament dynamics three-dimensionally. If we assume that the filament size on the cross section is a few times as large as ρ e m i / m e and that the ion temperature is higher than the electron temperature, the poloidal symmetry of filament propagation is broken and the propagation velocity has the non-negligible poloidal component, where ρe is the electron Larmor radius. Then, it is observed that such propagation dynamics depend on the position on the magnetic field line, i.e., in the toroidal direction. As the ion temperature increases beyond the electron temperature, the perpendicular electric field in a filament varies greatly according to the toroidal position. Such a variation might arise from the presheath potential drop on the potential hill side in a filament. Thus, the toroidal dependence of the propagation dynamics appears.