Simulation of Plasma Expansion Using a Two-Timescale Accelerated Particle-In-Cell Method

Abstract

Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302 Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. COLISEUM is an application programming interface wliicli performs calculations of plasma propagation and interaction with arbitrary 3-D surfaces. The applications of COLISEUM are wide-ranging, but include simulating ion source configurations inside vacuum chambers and predicting sputtering and re-deposition on surfaces. COLISEUM allows users to easily define complicated 3-D geometries using off the shelf CAD software, then select from a set of plasma expansion models of varying fidelities and numerical complexity to perform the solution. Once the object surfaces are created, the user can run different types of simulations for the same geometry. With this system, low fidelity models can be used to verify the geometry and boundary conditions, and to obtain first-order predictions. Higher fidelity models are then used to obtain more accurate predictions with greater cost in computation time. Detailed plasma expansion calculations are performed with a particle-in-cell (PIC) algorithm which includes vvall collisions and wall recombination. This paper presents an acceleration scheme which temporarily decouples the ion and neutral propagation loops to speed convergence. REPORT DATE (DD-MM-YYYY)

Investigation of Particle-in-Cell Acceleration Techniques for Plasma Simulations

“…Gibbons et al 3 also demonstrated the subcycling technique in which the slower moving neutrals are propagated at a larger time step than the faster moving ions. Gibbons et al 4 demonstrated the use of the subcycling scheme with a scheme that decoupled the modeling of surface interactions from the plume propagation. It utilizes particle sources from the surfaces in place of the self-consistent surface interaction modeling.…”