Influence of External Magnetic Field on Characteristics of Pinching Plasma Streams

Quasistationary plasma accelerators (QSPAs) can be used for diverse applications, including plasmasurface interaction experiments in the conditions close to the fusion reactor transient events (e.g., current disruptions, VDE, and giant ELMs), modifying material surfaces, and creating new surface alloys [1]. A magnetoplasma compressor (MPC), a QSPA-type device capable of generating pinching plasma streams with densities up to $10^{19}-10^{20} \mathrm{~cm}^{-3}$, can be further enhanced by applying an additional magnetic field, opening the possibility for improved discharge characteristics and plasma parameters [2]. The influence of an external magnetic field in the discharge channel of the MPC on the plasma stream dynamics was studied. The complex structure of the plasma stream undergoes significant changes when exposed to an external magnetic field: the magnitude of the electric potential and current increases, fewer current vortices tend to form. The external magnetic field improves the compression characteristics of the plasma flow, in particular, it increases the compression zone size and radial component of the $\mathrm{J} \times \mathrm{B}$ force. Introducing a magnetic field causes the current-sheet-like structure found in our recent research [2] to form earlier. These results significantly expand the range of possible applications of the device.