TY - JOUR
T1 - Generation of magnetic fields by the stationary accretion shock instability
AU - Endeve, Eirik
AU - Cardall, Christian Y.
AU - Budiardja, Reuben D.
AU - Mezzacappa, Anthony
PY - 2010
Y1 - 2010
N2 - We begin an exploration of the capacity of the stationary accretion shock instability (SASI) to generate magnetic fields by adding a weak, stationary, and radial (but bipolar) magnetic field, and in some cases rotation, to an initially spherically symmetric fluid configuration that models a stalled shock in the post-bounce supernova environment. In axisymmetric simulations, we find that cycles of latitudinal flows into and radial flows out of the polar regions amplify the field parallel to the symmetry axis, typically increasing the total magnetic energy by about 2 orders of magnitude. Non-axisymmetric calculations result in fundamentally different flows and a larger magnetic energy increase: shearing associated with the SASI spiral mode contributes to a widespread and turbulent field amplification mechanism, boosting the magnetic energy by almost 4 orders of magnitude (a result which remains very sensitive to the spatial resolution of the numerical simulations). While the SASI may contribute to neutron star magnetization, these simulations do not show qualitatively new features in the global evolution of the shock as a result of SASI-induced magnetic field amplification.
AB - We begin an exploration of the capacity of the stationary accretion shock instability (SASI) to generate magnetic fields by adding a weak, stationary, and radial (but bipolar) magnetic field, and in some cases rotation, to an initially spherically symmetric fluid configuration that models a stalled shock in the post-bounce supernova environment. In axisymmetric simulations, we find that cycles of latitudinal flows into and radial flows out of the polar regions amplify the field parallel to the symmetry axis, typically increasing the total magnetic energy by about 2 orders of magnitude. Non-axisymmetric calculations result in fundamentally different flows and a larger magnetic energy increase: shearing associated with the SASI spiral mode contributes to a widespread and turbulent field amplification mechanism, boosting the magnetic energy by almost 4 orders of magnitude (a result which remains very sensitive to the spatial resolution of the numerical simulations). While the SASI may contribute to neutron star magnetization, these simulations do not show qualitatively new features in the global evolution of the shock as a result of SASI-induced magnetic field amplification.
KW - Magnetohydrodynamics (MHD)
KW - Methods: numerical
KW - Stars: magnetic field
KW - Supernovae: general
UR - http://www.scopus.com/inward/record.url?scp=77950687697&partnerID=8YFLogxK
U2 - 10.1088/0004-637X/713/2/1219
DO - 10.1088/0004-637X/713/2/1219
M3 - Article
AN - SCOPUS:77950687697
SN - 0004-637X
VL - 713
SP - 1219
EP - 1243
JO - Astrophysical Journal
JF - Astrophysical Journal
IS - 2
ER -