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

JOURNAL OF COMPUTATIONAL PHYSICS

卷:420

Article

Stanier, A.¹  Chacon, L.¹  Le, A.¹ 

[1] Los Alamos Natl Lab, Appl Math & Plasma Phys, Los Alamos, NM 87545 USA

关键词: Hybrid;    Particle-in-cell;    Plasma;    Asymptotic-preserving;    Cancellation problem;    Space weather;   

DOI  :  10.1016/j.jcp.2020.109705

来源: Elsevier

【 摘 要 】

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 different spatial discretizations of ions as finite-spatial-size particles and electrons as a grid-based fluid can lead to significant numerical wave dispersion errors in the long wavelength limit (kd(i) << 1, where k is the wavenumber and d(i) is the ion skin-depth). The problem occurs when high-order particle-grid interpolations, or grid-based smoothing, spreads the electric field experienced by the ions across multiple spatial cells and leads to inexact cancellation of electric field terms in the total (ion + electron) momentum equation. Practical requirements on the mesh spacing Delta x/d(i) are suggested to bound these errors from above. The accuracy impact of not respecting these resolution constraints is shown for a non-linear shock problem. (C) 2020 Elsevier Inc. All rights reserved.

【 授权许可】

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