Kinetic and Electromagnetic simulation of Electrodeless Plasma Thrusters

Electrodeless plasma thrusters (EPTs) deliver energy to the plasma via electromagnetic waves, and generate magnetic thrust with a magnetic nozzle. Examples include the helicon plasma thruster (HPT) and the electron-cyclotron resonance thruster (ECRT). While prototypes are at various advanced stages of development, general EPT thrust efficiency is still low. Understanding and addressing the reasons for the low performance of EPTs requires an improved understanding of the physics of the wave-plasma interaction, the internal transport, and the external expansion in the magnetic nozzle.

This invited talk covers three recent advances in EPT modeling and simulation. First, we present hybrid PIC/fluid/wave simulations of an ECRT with a focus in the study of the plasma-wave interaction (propagation and absorption). A discussion of the numerical scheme to avoid spurious wave solutions is presented, followed by a parametric investigation with the operating parameters (mass flow and power) to identify trends in the thruster performance.

Second, a novel 2D+1 full particle in cell (PIC) model of a magnetic nozzle, which relies on 2D finite differences for in-plane dynamics and Fourier decomposition for azimuthal dynamics, is presented and used to study plasma oscillations. The model outperforms 3D full PIC finite differences discretization in terms of runtime.

Thirdly, last results on energy-conserving, time-implicit, electromagnetic PIC modeling are presented for a quasi-1D magnetic nozzle plasma expansion subject to applied waves. It is shown that absorption of the wave energy occurs at a localized position corresponding to a resonance, affecting the plasma profiles for sufficiently large EM power.