Electrostatic Ion Thrusters ‐ Towards Predictive Modeling

Abstract

Abstract. For satellite missions, thrusters have to be qualified in large vacuum vessels to simulate the space environment. One caveat of these experiments is the possible modification of the beam properties due to the interaction of the energetic ions with the vessel walls. Impinging ions can produce sputtered impurities or secondary electrons from the wall. These can stream back into the acceleration channel of the thruster and produce co-deposited layers. Over a long operation time of thousands of hours, these layers can modify the optimized geometry and induce changes in the ion beam properties, e.g., broadening of the angular distribution and thrust reduction. A Monte Carlo code for simulating the interaction of ion thruster beams with vessel walls was developed to study these effects. Back-fluxes of a SPT-like ion thruster for two different test-setups and vessel geometries are calculated.

Particle‐in‐cell simulation of an optimized high‐efficiency multistage plasma thruster

“…The anomalous transport is a 3D effect and to apply it in the 2d3v PIC-MCC model an effective anomalous transport coefficient is used for a random walk model in the velocity space. [11] This model is similar to a Bohm-like diffusion, with the transport coefficient D scaling with the electron temperature T e and the inverse of the magnetic field D ∝ T e /B. With self-consistent 3D simulations the value of the diffusion coefficient was deduced.…”

“…By scattering collisions and anomalous diffusion, transport across magnetic field lines occurs. The anomalous transport is a 3D effect and to apply it in the 2d3v PIC‐MCC model an effective anomalous transport coefficient is used for a random walk model in the velocity space . This model is similar to a Bohm‐like diffusion, with the transport coefficient D scaling with the electron temperature T e and the inverse of the magnetic field D ∝ T e / B .…”

“…This model is similar to a Bohm‐like diffusion, with the transport coefficient D scaling with the electron temperature T e and the inverse of the magnetic field D ∝ T e / B . With self‐consistent 3D simulations the value of the diffusion coefficient was deduced . The resulting electron energy diffusion perpendicular to the magnetic field lines increases, leading to a transport of the electrons from the outer to the inner magnetic bottle.…”

“…The electron mean-free paths in HEMP-Ts are of the same range as the system size and kinetic effects in the magnetic cusps create non-Maxwellian perturbations of the electron distribution function. [11] Hence, a kinetic simulation of the system is necessary for accurate analysis. [12,13] In this work an electrostatic 2D3v PIC method with a Monte Carlo Collision model [14] is applied.…”

Fluid Simulation of a Cusped Field Thruster

“…In terms of the simulation study, many people simulated the cusped field thrusters with PIC method [8,11,12]. Although PIC model can reflect the parameter distribution characteristics to some extent, it still has the problem of huge calculated amount, which leads to the difficulty in convergence.…”