A cancellation problem in hybrid particle-in-cell schemes due to finite particle size

A. Stanier; L. Chacon; A. Le

doi:10.1016/j.jcp.2020.109705

paper

A cancellation problem in hybrid particle-in-cell schemes due to finite particle size

arXiv:1912.04860 · doi:10.1016/j.jcp.2020.109705

Abstract

The quasi-neutral hybrid particle-in-cell algorithm with kinetic ions and fluid electrons is a popular model to study multi-scale problems in laboratory, space, and astrophysical plasmas. Here, it is shown that the treatment of ions as finite-size particles and electrons as a grid-based fluid can cause significant numerical wave dispersion errors in the magnetohydrodynamic limit ( $k d_{i} ≪ 1$ , where $d_{i}$ is the ion skin-depth). Practical requirements on the mesh spacing $Δ x / d_{i}$ are suggested to bound these errors from above.