SASI Shear and Magnetic Field Amplification
Abstract
We use time-dependent, two-dimensional hydrodynamic simulations including a passive magnetic field to quantify the amplification of progenitor magnetic fields by the strong shear created by the non-axisymmetric mode of the spherical accretion shock instability. During the linear growth phase of the instability, the total magnetic field energy scales with the energy of the SASI wave, which grows with an exponential timescale of 23 msec. The exponential growth of the field in the post-shock cavity ceases when the flux of magnetic energy deposited onto the proto-neutron star balances the rate at which the turbulent motions generated by the SASI amplify the magnetic field. The net result is that the magnetic energy in the shocked accretion flow below the supernova shock can increase by three orders of magnitude in ∼ 300 msec, and substantial magnetic flux can be deposited onto the proto-neutron star during the few hundred milliseconds that the accretion shock is trapped in the core.
- Publication:
-
American Astronomical Society Meeting Abstracts #216
- Pub Date:
- May 2010
- Bibcode:
- 2010AAS...21642804A