EFFECTS OF RESISTIVITY ON MAGNETIZED CORE-COLLAPSE SUPERNOVAE

• Published in: The Astrophysical journal 2013-02, Vol.764 (1), p.1-38
• Main Authors: Sawai, H, Yamada, S, Kotake, K, Suzuki, H
• Format: Article
• Language: English
• Subjects: ACCELERATION; ADVECTION; AMPLIFICATION; ASPECT RATIO; ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CALCULATION METHODS; Computation; Electrical resistivity; ERUPTION; EXPLOSIONS; MAGNETIC FIELDS; MAGNETOHYDRODYNAMICS; MATTER; PLASMA MACROINSTABILITIES; Rotating; ROTATION; SIMULATION; SUPERNOVAE; TWO-DIMENSIONAL CALCULATIONS
• ISSN: 0004-637X; 1538-4357
• DOI: 10.1088/0004-637X/764/1/10

We studied the role of turbulent resistivity in the core-collapse of a strongly magnetized massive star, carrying out two-dimensional resistive-MHD simulations. Three cases with different initial strengths of magnetic field and rotation are investigated: (1) a strongly magnetized rotating core, (2) a moderately magnetized rotating core, and (3) a very strongly magnetized non-rotating core. In each case, one ideal-MHD model and two resistive-MHD models are computed. As a result of these computations, each model shows an eruption of matter assisted by magnetic acceleration (and also by centrifugal acceleration in the rotating cases). We found that resistivity attenuates the explosion in cases 1 and 2, while it enhances the explosion in case 3. We also found that in the rotating cases, the main mechanisms for the amplification of a magnetic field in the post-bounce phase are an outward advection of the magnetic field and a twisting of poloidal magnetic field lines by differential rotation, which are somewhat dampened down with the presence of resistivity. Although magnetorotational instability seems to occur in the rotating models, it plays only a minor role in magnetic field amplification. Another impact of resistivity is that on the aspect ratio. In the rotating cases, a large aspect ratio of the ejected matter, >2.5, attained in an ideal-MHD model is reduced to some extent in a resistive model. These results indicate that resistivity possibly plays an important role in the dynamics of strongly magnetized supernovae.