Ann Almgren, Center for Computational Sciences and Engineering, Lawrence Berkeley National Lab

Friday March 2nd, 4pm, Phillips 332
(refreshments served in Phillips 330 starting at 3:30)

Low Mach Number Modeling of Type Ia Supernovae

Abstract: Type Ia supernovae (SNe Ia) are the largest thermonuclear explosions in the universe, and of considerable astrophysical and cosmological significance. Numerical modeling of SNe Ia has traditionally relied on discretizations of the fully compressible equations for fluid dynamics, supplemented by equations describing the thermonuclear reactions and heat release. The low Mach number formulation, by contrast, analytically removes acoustic wave propagation while retaining the compressibility effects resulting from nuclear burning, radial stratification, and large-scale heating. This formulation generalizes low Mach number models used in terrestrial atmospheric modeling and combustion to arbitrary equations of state such as those describing the degenerate matter found in stellar material. The low Mach number formulation results in a substantial improvement in computational efficiency compared to a compressible formulation, enabling calculations of supernova ignition which have previously been intractable.