A particle-in-cell Monte Carlo collision model is developed to explore dominant collisional effects on high-velocity xenon ions incident a quiescent gas at low neutral pressures. The range of pressure and collisionality examined are applicable for electric propulsion as well plasma processing devices; therefore, the computational technique described herein can be applied more complex simulations those devices. Momentum resonant charge-exchange collisions between background neutrals...

Abstract : The Spacecraft Multi-Scale/Multi-Physics Universal Research Framework (SM/MURF) is currently in development at the in-space propulsion branch of Air Force Laboratory (AFRL). This framework unifies multiple research codes developed independently this and intended to simulate plasma under a wide range time length scales relevant spacecraft electric (EP) systems. current effort focuses on modernization AFRL plume simulation tool, COLISEUM. In paper, all operations for are reviewed...

An experimental effort was used to examine the primary electron loss behavior for micro-scale (≲3 cm diameter) discharges. The experiment uses an flood gun source and axially aligned arrangement of ring-cusps guide electrons a downstream point cusp. Measurements current collected at cusp show unexpectedly complex pattern with azimuthally periodic structures. Additionally, in contrast conventional theory losses, overall radii measured collection areas are over order magnitude larger than...

When designing spacecraft with electric propulsion (EP) devices, it is important to assess integration ensure that the components are not subject significant sputtering by high-energy ions. In addition EP device and its plume, surface charging of has be modeled properly, as potential can directly affect rate. Three models incorporated into module numerical simulation framework-Thermophysics Universal Research Framework (TURF), these include: 1) dielectric; 2) conductive; 3) charge...

on high velocity ions incident to a quiescent gas, as examined in an ion gun experiment being carried out by UCLA researchers. Two dierent collision mechanisms are implemented the computational model: elastic and charge exchange (CEX) collisions. Because of very low ionization level observed beam experiment, Coulomb is not incorporated model. The two types approximated models depending particle energy: variable hard sphere model classical scattering with repulsive interaction potential....

Relaxing the direct simulation Monte Carlo (DSMC) method to be compatible with variable particle weights has significant advantages when applied simulations a large density variation, as statistical noise in low region can controlled. The stochastic weighted [S. Rjasanow and W. Wagner, J. Comput. Phys. 124, 243–253 (1996)] enables control of weight but never been multicomponent gas mixture or plasma. This paper focuses on charge-exchange collisions, is applicable any interspecies collision...

To address noise inherent in electronic data acquisition systems and real-world sources, Araki et al. [Phys. D, 417 (2021), 132819] demonstrated a grid-based nonlinear technique to remove from chaotic signal, leveraging clean high-fidelity signal the same dynamical system ensemble averaging multidimensional phase space. This method achieved denoising of time series with 100% added but suffered regions low density. improve this method, here an unstructured mesh based on triangulations Voronoi...

For this study, we use a combined experimental and computational approach to investigate the near-surface dynamics structure of plasma confined by permanent magnet cusp. Improved understanding in region allows electric propulsion designers take advantage cusp confinement for micro-scale discharges (≤ 1 cm), enabling high performance microthrusters that are attractive both microsatellite formation flying missions. An electron gun experiment designed specifically effort provides detailed data...

In the plumes of Hall thrusters and ion thrusters, high energy ions experience elastic collisions with slow neutral atoms. These involve a process momentum exchange, altering initial velocity vectors collision pair. addition to exchange process, atoms can electrons, resulting in charge-exchange fast these simulations, it is particularly important accurately perform computations ion-atom determining plume current profile assessing integration spacecraft components. The existing models are...

Free molecule regime is found in many problems, and of particular interest a transport gas high vacuum space or inside chamber. These problems are traditionally solved by particle method even though the susceptible to statistical noise. To date, radiosity view factor model has been applied free molecular flow problems. While this superior both speed smoothness density distribution, can only be source with Maxwellian distribution no streaming velocity. This study extended compatible any...

Ring-cusp discharges use multiple permanent magnet rings to facilitate confinement of the high energy electrons and other plasma species. The magnetic field configuration consists converging fields toward cusps with a large ratio maximum minimum strength. In such configurations, fluid simulation regular mesh can lead undesirable numerical diffusion errors caused by anisotropicity misalignment grid field. this paper, details custom technique for aligned (MFA) generation are provided. MFA...

An improved understanding of the electron loss behavior for permanent magnet cusps is needed to enable design efficient micro-scale plasma devices. Such devices can be used a variety applications, including high performance micro-thrusters that are attractive primary propulsion microsatellites, secondary larger spacecraft, and formation flying. Conventional theory magnetic generally relates area an analytical expression related field strength at surface. In contrast, this study examines...