Partial entropic stabilization of lattice Boltzmann magnetohydrodynamics

Area of Science:

• Computational physics
• Plasma physics
• Magnetohydrodynamics

Background:

• The entropic lattice Boltzmann algorithm is a computational method for fluid dynamics.
• Magnetohydrodynamics (MHD) describes the behavior of electrically conducting fluids in magnetic fields.
• Simulating complex plasma phenomena requires robust numerical methods.

Purpose of the Study:

• To extend the entropic lattice Boltzmann algorithm to MHD simulations.
• To incorporate magnetic field reversal capabilities into the algorithm.
• To validate the extended algorithm against known plasma instabilities.

Main Methods:

• Partial extension of the entropic lattice Boltzmann algorithm using the Dellar model for magnetic fields.
• Application of the entropic ansatz to scalar particle distribution functions.
• Utilization of a 9-bit lattice for 2D simulations of particle and magnetic distributions.

Main Results:

• The extended algorithm successfully simulated magnetic field reversal scenarios.
• Benchmarking against a multiple relaxation lattice-Boltzmann model for Kelvin-Helmholtz instability showed good agreement.
• Comparison with direct algorithms for Kelvin-Helmholtz/tearing mode and Orszag-Tang vortex models yielded accurate results.

Conclusions:

• The extended entropic lattice Boltzmann algorithm provides a viable method for MHD simulations, including those with magnetic field reversal.
• The approach accurately captures key plasma instabilities, demonstrating its potential for complex astrophysical and laboratory plasma research.