Esgee to Present at SCTC 2018: Modeling of Spacecraft Charging in GEO orbit

Esgee to Present at SCTC 2018: Modeling of Spacecraft Charging in GEO orbit

Esgee will present “High-fidelity Multi-Length Scale Modeling of Spacecraft Charging in GEO orbit” at the 15th Spacecraft Charging Technology Symposium 25-29 June, 2018 at the Integrated Research Center of Kobe University in Japan.

 

Abstract

This study describes high-fidelity modeling of spacecraft charging in GEO orbit environment and the resulting incipient vacuum arcing on the spacecraft’s surface. A satellite in GEO environment is subject to continuous bombardment by highly energetic charged particles that accumulate over time on dielectric surfaces resulting in differential voltages between surfaces.  For sufficiently large differential voltages, the electric field at sharp corners or protrusions may exceed the threshold for field electron emission that is accompanied by explosive emission of material from the feature.  This event constitutes the start of a vacuum arcing event with resulting damage to the spacecraft structure.  In this work, a high-fidelity computational model with unstructured meshing framework is used.  This framework allows of a multi-length scale resolution of small spacecraft features while fully representing the entire spacecraft geometry.  The self-consistent electrostatic potential equation is solved in conjunction with particle tracking to resolve electric-field profiles on the spacecraft surface. Further, the effects of a variety of surface electron emission processes (including secondary electron and photoelectron emission) is represented.

 

Esgee to Present at SCTC 2018: Hybrid Model of RF Gridded Ion Thruster

Esgee to Present at SCTC 2018: Hybrid Model of RF Gridded Ion Thruster

Esgee will present “Hybrid Fluid-Particle Plasma Modeling of a Radio-Frequency Gridded Ion” at the 15th Spacecraft Charging Technology Symposium 25-29 June, 2018 at the Integrated Research Center of Kobe University in Japan.

 

Abstract

We present a hybrid, fluid-particle plasma model that is used to investigate the plasma discharge and ion extraction behaviors of a radio-frequency gridded ion thruster (RIT). The hybrid approach combines a fluid formulation for plasma governing equations with a kinetic particle formulation for ion behaviors. The self-consistent plasma model includes fully coupled electromagnetics and RF circuit models. Ion particles are dynamically generated from ionization rates in the discharge and tracked as they are extracted from the chamber by a series of electrostatically biased grids. This hybrid approach offers an accurate representation of ion optics coupled with an efficient representation of bulk plasma discharge and chamber operating conditions within a single coupled simulation.

Results are presented for an axisymmetric model of an RIT-3.5. Predicted ion density distributions and ion optics are compared to literature with reasonable agreement. Performance sensitivity to grid potentials are studied to demonstrate model application to thruster performance optimization. The OverViz Simulation Suite, with coupled non-equilibrium plasma and kinetic particle modules, is used to perform the simulations.