Numerical analysis of standing accretion shock instability with neutrino heating in supernova cores

Naofumi Ohnishi, Kei Kotake, Shoichi Yamada

Research output: Contribution to journalArticlepeer-review

145 Citations (Scopus)

Abstract

We have numerically studied the instability of the spherically symmetric standing accretion shock wave against nonspherical perturbations. We have in mind the application to collapse-driven supernovae in the postbounce phase, where the prompt shock wave generated by core bounce is commonly stalled. We take an experimental standpoint in this paper. Using spherically symmetric, completely steady, shocked accretion flows as unperturbed states, we have clearly observed both the linear growth and the subsequent nonlinear saturation of the instability. In so doing, we have employed a realistic equation of state, together with heating and cooling via neutrino reactions with nucleons. We have performed a mode analysis based on the spherical harmonics decomposition and found that the modes with l = 1, 2 are dominant not only in the linear regime but also after nonlinear couplings generate various modes and saturation occurs. By varying the neutrino luminosity, we have constructed unperturbed states both with and without a negative entropy gradient. We have found that in both cases the growth of the instability is similar, suggesting that convection does not play a dominant role, which also appears to be supported by the recent linear analysis of the convection in accretion flows by Foglizzo et al. The oscillation period of the unstable l = 1 mode is found to fit better with the advection time rather than with the sound crossing time. Whatever the cause may be, the instability favors a shock revival.

Original languageEnglish
Pages (from-to)1018-1028
Number of pages11
JournalAstrophysical Journal
Volume641
Issue number2 I
DOIs
Publication statusPublished - 2006 Apr 20

Keywords

  • Hydrodynamics
  • Instabilities
  • Neutrinos
  • Supernovae: general

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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