The Magnetorotational Instability in Core-Collapse Supernova Explosions

By S. Akiyama, J. C. Wheeler, D. Meier, Itamar Lichtenstadt University of Texas at Austin, Jet propulsion Laboratory, Hebrew University of Jerusalem. 2002

347 citations recorded by the source corpus.

We investigate the action of the magnetorotational instability (MRI) in the context of iron-core collapse. Exponential growth of the field on the timescale Ω-1 by the MRI will dominate the linear growth process of field-line "wrapping" with the same characteristic time. We examine a variety of initial rotation states, with solid-body rotation or a gradient in rotational velocity, that correspond to models in the literature. A relatively modest value of the initial rotation, a period of ~10 s, will give a very rapidly rotating proto-neutron star and hence strong differential rotation with respect to the infalling matter. We assume conservation of angular momentum on spherical shells. Rotational distortion and the dynamic feedback of the magnetic field are neglected in the subsequent calculation of rotational velocities. In our rotating and collapsing conditions, a seed field is expected to be amplified by the MRI and to grow exponentially to a saturation field. Results are discussed for two examples of saturation fields, a fiducial field that corresponds to vA = rΩ and a field that corresponds to the maximum growing mode of the MRI. We find, as expected, that the shear is strong at the boundary of the newly formed proto-neutron star and, unexpectedly, that the region within the stalled shock can be subject to strong MHD activity. Modest initial rotation velocities of the iron core result in sub-Keplerian rotation and a sub-equipartition magnetic field that nevertheless produce substantial MHD luminosity and hoop stresses: saturation fields of order 1015-1016 G can develop ~300 ms after bounce with an associated MHD luminosity of ~1052 ergs s-1. Bipolar flows driven by this MHD power can affect or even cause the explosions associated with core-collapse supernovae.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/9be7d96d4c50da6cded1a70c0532d6ebd5e59635

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Citations in the corpus

Explosion mechanism, neutrino burst and gravitational wave in core-collapse supernovae (2005, methodology): “Although there remains concern of the treatment of the rotation and magnetic fields in the above 1D model computations [4, 365], the obtained implications seem to be important and should be examined by the multidimensional MHD simulations [365].”
Colloquium: Perspectives on core-collapse supernova theory (2012, background): “Rapid rotation with magnetic fields should naturally lead to vigorous explosions and this MHD mechanism has a long history (LeBlanc & Wilson 1970; Symbalisty 1984; Akiyama et al. 2003; Akiyama & Wheeler 2005).”
Viscosity and Rotation in Core-Collapse Supernovae (2004, background): “We address this conclusion in x 5 and find that large fields in the range 1014–1016 G can be typical in rotating core collapse (Duncan & Thompson 1992; Thompson & Duncan 1993), in agreement with Akiyama et al. (2003).”
The Proto-Magnetar Model for Gamma-Ray Bursts (2010, background): “…may go hand-in-hand in core collapse because differential rotation provides a source of free energy to power field growth, via e.g. an α − Ω dynamo in the convective proto-NS (Duncan & Thompson 1992) or the magneto-rotational instability (MRI; e.g. Akiyama et al. 2003; Thompson et al. 2005).”
BLACK HOLE FORMATION IN FAILING CORE-COLLAPSE SUPERNOVAE (2010, methodology): “This is common practice in stellar evolution codes (e.g., Heger et al. 2000) an hs also been applied to Newtonian 1D stellar collapse calculations (Akiyama et al. 2003; Thompson et al. 2005).”
Semi-global simulations of the magneto-rotational instability in core collapse supernovae (2008, background): “As pointed out by Akiyama et al. (2003), the conditions for the instability are fulfilled in typical post-collapse supernova cores.”
Simulations of Magnetically Driven Supernova and Hypernova Explosions in the Context of Rapid Rotation (2007, background): “Furthermore, all reasonable initial conditions result in PNSs with differential rotation and shear (Akiyama et al. 2003).”
THE r-PROCESS NUCLEOSYNTHESIS IN THE VARIOUS JET-LIKE EXPLOSIONS OF MAGNETOROTATIONAL CORE-COLLAPSE SUPERNOVAE (2015, background): “The role of MRI during core-collapse has been studied, focusing on several aspects (Akiyama et al. 2003; Obergaulinger et al. 2009; Masada et al. 2012; Obergaulinger et al. 2014; Masada et al. 2015).”
Numerical Analysis of Standing Accretion Shock Instability with Neutrino Heating in Supernova Cores (2005, background): “…Yamada & Sato 1994; Shimizu et al. 2001; Kotake et al. 2003; Yamasaki & Yamada 2005; Walder et al. 2005), and magnetic fields (Ardeljan et al. 2000; Akiyama et al. 2003; Kotake et al. 2004; Yamada & Sawai 2004; Kotake et al. 2005) (see for a review, Kotake et al. (2005) and references therein).”
Two-Dimensional Multiangle, Multigroup Neutrino Radiation-Hydrodynamic Simulations of Postbounce Supernova Cores (2008, methodology): “…et al. (2007) (the latter for the accretion-induced collapse scenario) have shown that energetic MHD-driven explosions may be obtained if field-amplification by the magneto-rotational instability (Balbus & Hawley 1991) is as efficient in the core-collapse context as suggested (Akiyama et al. 2003).”