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Advanced Stellar Modeling: Magnetohydrodynamic Simulations of White Dwarf Mergers

Project · Astrophysics · HPC

dens_slice_plt
dens_slice_plt
Evolution of a White dwarf merger. The simulation was done using the unsplit staggered mesh MHD solver in FLASH. The movie shows Beta (ratio of gas pressure to magnetic pressure) varying with time. The image is a density slice plot with a resolution of (256 × 256) cells at 1050 sec after the merger.
Project Overview

This project involved the application of advanced computational techniques to simulate and analyze complex White Dwarf merger events. Utilizing the Magnetohydrodynamic (MHD) equations, the study extended the understanding of magnetized stellar interactions for precise astronomical modeling.

MHD Formulation and Conservation Laws

The simulation relies on the MHD equations, encompassing the conservation of mass, momentum, energy, and magnetic induction. These equations are expressed as:

\(\frac{\partial \rho}{\partial t} + \nabla \cdot (\rho \mathbf{v}) = 0\) (Conservation of Mass)

\(\frac{\partial \rho \mathbf{v}}{\partial t} + \nabla \cdot (\rho \mathbf{v} \mathbf{v} - \mathbf{B} \mathbf{B}) + \nabla p^* = 0\) (Momentum Conservation)

\(\frac{\partial E}{\partial t} + \nabla \cdot [(E + p^*) \mathbf{v} - \mathbf{B}(\mathbf{v} \cdot \mathbf{B})] = 0\) (Energy Conservation)

\(\frac{\partial \mathbf{B}}{\partial t} = \nabla \times (\mathbf{v} \times \mathbf{B})\) (Magnetic Induction)

Here, \(\rho\) is the density, \(\mathbf{v}\) the velocity, \(\mathbf{B}\) the magnetic field, and \(p^*\) the total pressure including magnetic contributions.

Simulation Methodology

The simulations were conducted using the unsplit staggered mesh MHD solver in FLASH on the STAMPEDE 2 supercomputer. The project leveraged High-Performance Computing (HPC) for detailed analysis, facilitating comparison with traditional hydrodynamic models. This exploration enhances current astronomical understanding, offering novel insights into the intricate dynamics of stellar mergers.

White Paper

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