A Robust Method for Handling Low Density Regions in Hybrid Simulations for Collisionless Plasmas

Abstract

A robust method to handle vacuum and near vacuum regions in hybrid simulations for space and astrophysical plasmas is presented. The conventional hybrid simulation model dealing with kinetic ions and a massless charge-neutralizing electron fluid is known to be susceptible to numerical instability due to divergence of the whistler-mode wave dispersion, as well as division-by-density operation in regions of low density. Consequently, a pure vacuum region is not allowed to exist in the simulation domain unless some ad hoc technique is used. To resolve this difficulty, an alternative way to introduce finite electron inertia effect is proposed. Contrary to the conventional method, the proposed one introduces a correction to the electric field rather than the magnetic field. It is shown that the generalized Ohm's law correctly reduces to Laplace's equation in a vacuum which therefore does not involve any numerical problems. In addition, a variable ion-to-electron mass ratio is introduced to reduce the phase velocity of high frequency whistler waves at low density regions so that the stability condition is always satisfied. It is demonstrated that the proposed model is able to handle near vacuum regions generated as a result of nonlinear self-consistent development of the system, as well as pure vacuum regions set up at the initial condition, without losing the advantages of the standard hybrid code.

arXiv comment19 pages, 9 figures, accepted by Journal of Computational Physics

References in corpus (4)

• The interaction between the Moon and the solar wind
• The Relation between Ion Temperature Anisotropy and Formation of Slow Shocks in Collisionless Magnetic Reconnection
• Detailed Structure and Dynamics in Particle-in-Cell Simulations of the Lunar Wake
• Handling vacuum regions in a hybrid plasma solver

Cited by in corpus (11)

• A fully implicit, conservative, non-linear, electromagnetic hybrid particle-ion/fluid-electron algorithm
• A new hybrid code (CHIEF) implementing the inertial electron fluid equation without approximation
• Observations and modelling of ion cyclotron emission observed in JET plasmas using a sub-harmonic arc detection system during ion cyclotron resonance heating
• Divergence-free Approximate Riemann Solver for the Quasi-neutral Two-fluid Plasma Model
• A Generalized Quasi-Neutral Fluid-Particle Hybrid Plasma Model and Its Application to Energetic-Particle-Magnetohydrodynamics Hybrid Simulation
• A Second-order Divergence-constrained Multidimensional Numerical Scheme for Relativistic Two-Fluid Electrodynamics
• Importance of accurate consideration of the electron inertia in hybrid-kinetic simulations of collisionless plasma turbulence: 1. The 2D limit
• A conservative implicit-PIC scheme for the hybrid kinetic-ion fluid-electron plasma model on curvilinear meshes
• Electron inertia effects in 3D hybrid-kinetic collisionless plasma turbulence
• Maximus: a Hybrid Particle-in-Cell Code for Microscopic Modeling of Collisionless Plasmas
• Simulation of collisionless shocks in plasmas with high metallicity