Nonlinear instability of accelerating shock waves with application to supernovae

Details Nonlinear instability of accelerating shock waves with application to supernovae Nonlinear instability of accelerating shock waves with application to supernovae

Nov 1994

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994apj...435..815l&link_type=abstract

Astrophysical Journal, Part 1 (ISSN 0004-637X), vol. 435, no. 2, p. 815-820

Computer Science

Numerical Analysis

15

Dynamic Stability, Nonlinear Systems, Numerical Differentiation, Perturbation, Shock Wave Propagation, Shock Waves, Stellar Atmospheres, Supernovae, Hydrodynamics, Numerical Analysis, X Ray Spectra

Scientific paper

We consider the stability of a planar accelerating shock front in an exponential atmosphere, a situation that can be described by a self-similar solution. A previous linear instability analysis showed that there are three regimes, depending on the wavelength of the perturbation along the direction of the shock front: at long wavelengths the shock is unstable, at intermediate wavelengths it is overstable, and at short wavelenghts it is stable, where the characteristic length is set by the initial density scale height. We have carried out numerical simulations of such an accelerating shock front and have confirmed the results of the semianalytic linear analysis in the linear regime. In the nonlinear regime, the evolution again depends on the three wavelength domains. At long wavelengths, the instability continuously grows but the flow remains smooth, and at short wavelengths, the flow is stable. The intermediate wavelength, overstable regime shows more complex evolution. The growing linear oscillations saturate soon after entering the nonlinear regime and the oscillations continue with the same approximate period. The shock front develops moving points of intersection, which generate weak shock fronts and density and pressure structure in the immediate postshock flow. The density fluctuations, with a contrast of a factor of 2-3, become frozen into the downstream flow. The growth of the instability is slow, so substantial initial perturbations are needed; these may be present in Type II supernovae with red supergiant progenitor stars which have outer convective regions. The clumping in the outer supernova atmosphere may affect spectral line formation and may play a role in the formation of fast knots.

Affiliated with

Also associated with

No associations

Rating

Nonlinear instability of accelerating shock waves with application to supernovae does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Nonlinear instability of accelerating shock waves with application to supernovae, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Nonlinear instability of accelerating shock waves with application to supernovae will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1022105