A semi-implicit, energy- and charge-conserving particle-in-cell algorithm for the relativistic Vlasov-Maxwell equations

JOURNAL OF COMPUTATIONAL PHYSICS

卷:407

Article

Chen, G.¹  Chacon, L.¹  Yin, L.¹  Albright, B. J.¹  Stark, D. J.¹  Bird, R. F.¹ 

[1] Los Alamos Natl Lab, Los Alamos, NM 87545 USA

关键词: Particle-in-cell;    Energy conservation;    Charge conservation;    Laser plasma interactions;   

DOI  :  10.1016/j.jcp.2020.109228

来源: Elsevier

【 摘 要 】

Conventional explicit electromagnetic particle-in-cell (PIC) algorithms do not conserve discrete energy exactly. Time-centered fully implicit PIC algorithms can conserve discrete energy exactly, but may introduce large dispersion errors in the light-wave modes. This can lead to intolerable simulation errors where accurate light propagation is needed (e.g. in laser-plasma interactions). In this study, we selectively combine the leap-frog and Crank-Nicolson methods to produce an exactly energy- and charge-conserving relativistic electromagnetic PIC algorithm. Specifically, we employ the leap-frog method for Maxwell's equations, and the Crank-Nicolson method for the particle equations. The semi-implicit formulation still features a timestep CFL, but facilitates exact global energy conservation, exact local charge conservation, and preserves the dispersion properties of the leapfrog method for the light wave. The algorithm employs a new particle pusher designed to maximize efficiency and minimize wall-clock-time impact vs. the explicit alternative. It has been implemented in a code named iVPIC, based on the Los Alamos National Laboratory VPIC code (https://github.com/iosalamos/vpic). We present numerical results that demonstrate the properties of the scheme with sample test problems: relativistic two-stream instability, Weibel instability, and laser-plasma instabilities. Published by Elsevier Inc.

【 授权许可】

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