The Effects of High-energy Tail Electrons in Magnetic Nozzle Plasma Flow: Preliminary Results from Fully Kinetic PIC Simulations

Magnetic nozzles are central to several electrodeless electric propulsion concepts. In typical MN plasma flows, electron velocity and energy distributions frequently deviate from Maxwellian equilibrium and typically have enhanced high-energy tails that may influence current formation. Motivated by this gap, we present our preliminary results from axisymmetric fully kinetic particle-in-cell simulations of a collisionless plasma beam expanding in an ECRT/HPT-type magnetic nozzle. We quantify the total azimuthal current and reconstruct the electron azimuthal current using a fluid-based full-moment formulation that retains ExB, diamagnetic, viscous-stress, and inertia-induced contributions. The reconstructed current shows consistent spatial trends with the directly deposited PIC current. The extracted electron energy probability function at representative downstream locations clearly departs from a local reconstructed Maxwellian form, indicating the presence of non-Maxwellian electrons. Detailed phase-space and parametric analyses will be presented in future work.