A Parallel-Kinetic-Perpendicular-Moment Model for Magnetized Plasmas

TL;DR

This paper introduces a novel hybrid model for magnetized plasmas that efficiently captures parallel particle dynamics and approximates perpendicular behavior, enabling larger-scale simulations with improved computational feasibility.

Contribution

The paper presents a new parallel-kinetic-perpendicular-moment model that combines spectral expansion with kinetic equations, extending traditional asymptotic models for magnetized plasmas.

Findings

Demonstrates the model's effectiveness in simulating shocks.

Shows applicability to magnetic reconnection scenarios.

Connects the model to existing asymptotic theories.

Abstract

We describe a new model for the study of weakly-collisional, magnetized plasmas derived from exploiting the separation of the dynamics parallel and perpendicular to the magnetic field. This unique system of equations retains the particle dynamics parallel to the magnetic field while approximating the perpendicular dynamics through a spectral expansion in the perpendicular degrees of freedom, analogous to moment-based fluid approaches. In so doing, a hybrid approach is obtained which is computationally efficient enough to allow for larger-scale modeling of plasma systems while eliminating a source of difficulty in deriving fluid equations applicable to magnetized plasmas. We connect this system of equations to historical asymptotic models and discuss advantages and disadvantages of this approach, including the extension of this parallel-kinetic-perpendicular-moment beyond the typical region of validity of these more traditional asymptotic models. This paper forms the first of a multi-part series on this new model, covering the theory and derivation, alongside demonstration benchmarks of this approach including shocks and magnetic reconnection.