SASI Rotation

SASI in a Spinning Star

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Blondin, J. M., Mezzacappa, A., & DeMarino, C. 2003, ApJ, 584, 971
Stability of Standing Accretion Shocks, With an Eye Toward Core Collapse Supernovae
Original discovery of the SASI. Attributed instability to Vortical Acoustic coupling described by Foglizzo, but is not (?) the case.

Blondin, J. M. & Shaw, S. 2007, ApJ, 656, 366
Linear Growth of Spiral SASI Modes in Core-Collapse Supernovae
Two-dimensional simulations in the equatorial plane are used to study non-axisymmetric modes of the SASI. These modes are excited by dropping a density perturbation onto the accretion shock. The perturbation is in the shape of a bar oriented at an angle with respect to the spherical shock. The result sends a wave rotating around the accreting star. The amplitude of the perturbation is tracked by computing the Fourier components of the angular velocity.

Blondin, J. M. & Mezzacappa, A. 2007, Nature, 445, 58
Pulsar Spins from an Instability in the Accretion Shock of Supernovae

Yamasaki, T. & Foglizzo, T. 2008, ApJ, 679, 607
Effect of Rotation on the Stability of a Stalled Cylindrical Shock and Its Consequences for Core-Collapse Supernovae

Laming, J. M. 2007, ApJ, 659, 1449
Analytic Approach to the Stability of Standing Accretion Shocks: Application to Core-Collapse Supernovae
This author used an approximate analytic method (following Vishniac & Ryu 1989) to find a dispersion relation for the modes of a spherical accretion shock. He found growing oscillations for low-order sloshing modes (l=1,2), in agreement with numerical simulations. For ratios of the shock radius to stellar radius appropriate to supernovae, he found the instability existed even when the advection terms were removed from the equations - hence the SASI is NOT dependent on advection and is NOT related to the Vortical Acoustic instability as originally proposed. He argues that growth rates will be higher with increasing rotation for m=1.


Last update May 22, 2008

Research by John M. Blondin Department of Physics, North Carolina State University