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A. Mezzacappa (Oak Ridge National Labs), J. M. Blondin (North Carolina State University)
We have explored the dynamics of the stalled accretion shock in core collapse supernovae using large-scale three-dimensional hydrodynamics simulations on the Cray X1 at the National Center for Computational Sciences (Oak Ridge National Laboratory). We confirmed the dominance of the l=1 mode of the SASI in the linear regime, as first seen in two-dimensional simulations. However, this mode does not survive long in the non-linear phase in 3D. The growing oscillation of the supernova shock wave gives way to an m=1 spiral mode in 3D. Once the initial axisymmetry is broken, the perturbations to the stalled accretion shock begin to propagate around the proto-neutron star, creating strong rotational flow within the interior of the accretion shock. Although the net angular momentum remains zero, the angular momentum of the gas accreting onto the proto-neutron star becomes very large, leading to a gradual spin-up of the proto-neutron star. This shock-induced rotational flow may also have important consequences on the dynamical evolution of any magnetic fields present in the post-bounce stellar core.
All of our 3D simulations are dominated at late times by strong non-axisymmetric modes that cannot exist in 2D models. These results clearly demonstrate the importance of using three-dimensional simulations to study core-collapse supernovae.
This work was performed under the auspices of the TeraScale Supernova Initiative, funded by SciDAC grants from the DOE Office of Science High-Energy, Nuclear, and Advanced Scientific Computing Research Programs.
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Bulletin of the American Astronomical Society, 37 #4
© 2005. The American Astronomical Soceity.