Particle-in-cell simulations of a multipole plasma trap including a boundary magnetic field

The multipole plasma trap (MPT) [1] is a three-dimensional confinement volume bounded by an envelope of radio-frequency (RF) electrodes. In this work, plasma interaction with the boundary field of the MPT is investigated via particle-in-cell (PIC) simulations using software such as VSim 12 [2] and PlasmaPy [3]. Spherical and cylindrical electrode geometries are considered, and a static multicusp magnetic field arrangement is added as well. Scenarios for trapping nonneutral and/or pair ion plasmas are investigated, as well as conventional plasma with quasineutrality provided by the electron species; the latter case depends particularly on optimization of the multicusp magnetic field. Energy modification (heating) of the plasma particle distribution at the MPT boundary due to the spatially inhomogeneous RF field is investigated. The PIC simulation work is conducted to inform experimental design of MPT configurations that reflect particle species (positive ions, negative ions, electrons) of varying incidence energy over a range of adjustable RF, magnetic field, and plasma parameters; specific experimental scenarios for electron and ion reflection and energy analysis are then identified.

[1] N. K. Hicks, A. Bowman, and K. Godden, Physics 1 (3), 392–401 (2019) doi:10.3390/physics1030028

[2] C. Nieter and J. R. Cary, J. Comput. Phys. 196, 448 (2004)

[3] PlasmaPy Community et al. (2023). PlasmaPy, version 2023.5.1, Zenodo, https://doi.org/10.5281/zenodo.8015753