An Energy Conserving Vlasov Solver That Tolerates Coarse Velocity Space Resolutions: Simulation of MMS Reconnection Events

TL;DR

This paper introduces a novel dual Vlasov solver that conserves energy and tolerates coarse velocity space resolutions, enabling large-scale kinetic simulations of magnetic reconnection with accuracy comparable to spacecraft observations.

Contribution

A new dual Vlasov solver combining positivity-preserving advection and energy-conserving PDEs improves efficiency and accuracy in coarse-resolution kinetic plasma simulations.

Findings

Successfully simulates Earth's magnetosphere reconnection events.

Achieves good agreement with MMS spacecraft measurements.

Enables large-scale kinetic modeling with reduced computational cost.

Abstract

Vlasov solvers that operate on a phase-space grid are highly accurate but also numerically demanding. Coarse velocity space resolutions, which are unproblematic in particle-in-cell (PIC) simulations, can lead to numerical heating or oscillations in standard continuum Vlasov methods. We present a new dual Vlasov solver which is based on an established positivity preserving advection scheme for the update of the distribution function and an energy conserving partial differential equation solver for the kinetic update of mean velocity and temperature. The solvers work together via moment fitting during which the maximum entropy part of the distribution function is replaced by the solution from the partial differential equation solver. This numerical scheme makes continuum Vlasov methods competitive with PIC methods concerning computational cost and enables us to model large scale reconnection in Earth's magnetosphere with a fully kinetic continuum method. The simulation results agree well with measurements by the MMS spacecraft.