Studies Toward the Modeling of White Dwarf Mergers and Magnetohydrodynamics
Type Ia supernovae are the product of a thermonuclear explosion consuming degenerate carbon and oxygen, indicating the presence of at least one white dwarf in their progenitor. Different models have been proposed for possible type Ia supernova progenitors as a result of diversity in observed spectra...
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| Format: | Dissertation |
| Language: | English |
| Published: |
ProQuest Dissertations & Theses
01-01-2020
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| Online Access: | Get full text |
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| Summary: | Type Ia supernovae are the product of a thermonuclear explosion consuming degenerate carbon and oxygen, indicating the presence of at least one white dwarf in their progenitor. Different models have been proposed for possible type Ia supernova progenitors as a result of diversity in observed spectra. In the WD merger scenario, the less massive WD in the binary system is tidally disrupted by the primary WD forming a disk. The primary WD then accretes carbon and oxygen generating the conditions for thermonuclear ignition. In order to understand the dynamics of the merger process and evolution, we develop 3D magneto- hydrodynamics simulations using the code Castro. Castro is a compressible hydrodynamics code supporting self-gravity, general equation of state and nuclear reactions, radiation, and magnetic fields. Castro is built on the AMReX library and uses a hybrid parallelization approach with MPI+X, where X is OpenMP for CPUs and CUDA for GPUs. In this work particular emphasis is placed on the ideal MHD implementation in Castro, which is based on the constrained transport formulation. The constrained transport technique defines face centered magnetic fields that evolve via edge centered electric fields. The MHD capability integrates well with both the physics and parallelization features that distinguish Castro. We also present results of 0.6 M +0.9 M WD merger systems with and without magnetic fields together with the construction of the initial magnetic dipole fields from the stars. Dur- ing and after the merger formation the magnetic pressure in the domain rises, though it is weak compared to the gas pressure. The setup introduced here could be utilized for further exploration with various parameters. |
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| ISBN: | 9798678178466 |