The product that will be developed under this proposal will directly benefit NASA by providing it with a tool capable of analyzing the influence of various system variables during the design process of new high power Hall thrusters. Possible uses include selection of wall materials to reduce electron energy losses, selection of wall materials to improve thruster lifetime, optimization of magnetic circuit to take advantage of effects such as the magnetic mirror and magnetic lens, optimization of thruster geometry by utilizing non-conventional designs such as cylindrical or multi-channel configuration, and optimizing the electron currents produced by the cathode to reduce plume divergence and thus reduce plume divergence. Predictive thruster model will in addition serve as a source model for plume modeling of the thruster integrated on a spacecraft. This will allow the mission designer to optimize the placement of the thruster on the spacecraft to reduce secondary interaction of plume particles with sensitive spacecraft sensors and components. The need to simplify the design and analysis, and reduce the inherent complexity of Hall thrusters is not limited to NASA. Other government entities, including the Air Force, have an existing need for such programs. Our effort will be applicable to both the high power Hall thrusters proposed by NASA, as well as low power thrusters being investigated by other government entities and commercial partners for near-Earth operations such as station keeping and orbit rising. The simulation tool that will be developed under this effort can thus also serve private industry, companies such as Aerojet, Busek that are developing Hall thrusters and will be able to use this predictive tool in the design process. In addition, we plan to leverage the lessons learned in this effort to further enhance multiscale modeling capability for rarefied gas applications. One such topic includes modeling of space environment interactions. The spacecraft community in large is in need of codes that can predict potential contamination and charging events, and their effect on spacecraft operation. Of interest is the wall interaction of plasma particles. The domains of interest (spacecraft system) are of size too large to allow direct modeling of wall interaction details. Multiscale modeling of the system is thus required.
More »