Numerical Study of the Vishniac Instability in Supernova Remnants
| Autor: | Serge Bouquet, H. C. Nguyen, Fabrice Roy, Claire Michaut, C. Cavet |
|---|---|
| Přispěvatelé: | Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7) |
| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Physics
Shock wave Radiative cooling 010308 nuclear & particles physics Astrophysics::High Energy Astrophysical Phenomena [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE] Astronomy and Astrophysics Astrophysics 01 natural sciences Instability Computational physics Supernova Space and Planetary Science 0103 physical sciences Radiative transfer Adiabatic process Supernova remnant 010303 astronomy & astrophysics Blast wave ComputingMilieux_MISCELLANEOUS |
| Zdroj: | The Astrophysical Journal The Astrophysical Journal, American Astronomical Society, 2012, 759 (2), pp.78. ⟨10.1088/0004-637X/759/2/78⟩ |
| ISSN: | 0004-637X 1538-4357 |
| DOI: | 10.1088/0004-637X/759/2/78⟩ |
| Popis: | The Vishniac instability is thought to explain the complex structure of radiative supernova remnants in their Pressure-Driven Thin Shell (PDTS) phase after a blast wave (BW) has propagated from a central explosion. In this paper, the propagation of the BW and the evolution of the PDTS stage are studied numerically with the two-dimensional (2D) code HYDRO-MUSCL for a finite-thickness shell expanding in the interstellar medium (ISM). Special attention is paid to the adiabatic index, γ, and three distinct values are taken for the cavity (γ1), the shell (γ2), and the ISM (γ3) with the condition γ2 < γ1, γ3. This low value of γ2 accounts for the high density in the shell achieved by a strong radiative cooling. Once the spherical background flow is obtained, the evolution of a 2D-axisymmetric perturbation is computed from the linear to the nonlinear regime. The overstable mechanism, previously demonstrated theoretically by E. T. Vishniac in 1983, is recovered numerically in the linear stage and is expected to produce and enhance anisotropies and clumps on the shock front, leading to the disruption of the shell in the nonlinear phase. The period of the increasing oscillations and the growth rate of the instability are derived from several points of view (the position of the perturbed shock front, mass fluxes along the shell, and density maps), and the most unstable mode differing from the value given by Vishniac is computed. In addition, the influence of several parameters (the Mach number, amplitude and wavelength of the perturbation, and adiabatic index) is examined and for wavelengths that are large enough compared to the shell thickness, the same conclusion arises: in the late stage of the evolution of the radiative supernova remnant, the instability is dampened and the angular initial deformation of the shock front is smoothed while the mass density becomes uniform with the angle. As a result, our model shows that the supernova remnant returns to a stable evolution and the Vishniac instability does not lead to the fragmentation of the shock as predicted by the theory. |
| Databáze: | OpenAIRE |
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