Thermonuclear Supernovae: Simulations of the Deflagration Stage and Their Implications

Gamezo, Vadim N.; Khokhlov, A. M.; Oran, Elaine S.; Chtchelkanova, Almadena; Rosenberg, Robert

doi:10.1126/science.1078129

Cited by 358 publications

(343 citation statements)

References 50 publications

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“…Here, the peak temperature is 6 ; 10 9 K. We see good agreement between the two compressible codes ( PPM and unsplit) and the low Mach number algorithm. (Röpke & Hillebrandt 2005;Plewa et al 2004;Gamezo et al 2003). The FLASH implementation of PPM has been well validated (Calder et al 2002), and serves as a good basis for comparisons with the low Mach number algorithm.…”

Section: Compressible Formulationsmentioning

confidence: 99%

Low Mach Number Modeling of Type Ia Supernovae. I. Hydrodynamics

Almgren

Bell

Rendleman

et al. 2006

ApJ

126

135

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We introduce a low Mach number equation set for the large-scale numerical simulation of carbon-oxygen white dwarfs experiencing a thermonuclear deflagration. Since most of the interesting physics in a Type Ia supernova transpires at Mach numbers from 0.01 to 0.1, such an approach enables both a considerable increase in accuracy and a savings in computer time compared with frequently used compressible codes. Our equation set is derived from the fully compressible equations using low Mach number asymptotics, but without any restriction on the size of perturbations in density or temperature. Comparisons with simulations that use the fully compressible equations validate the low Mach number model in regimes where both are applicable. Comparisons to simulations based on the more traditional anelastic approximation also demonstrate the agreement of these models in the regime for which the anelastic approximation is valid. For low Mach number flows with potentially finite amplitude variations in density and temperature, the low Mach number model overcomes the limitations of each of the more traditional models and can serve as the basis for an accurate and efficient simulation tool.

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Section: Compressible Formulationsmentioning

confidence: 99%

Low Mach Number Modeling of Type Ia Supernovae. I. Hydrodynamics

Almgren

Bell

Rendleman

et al. 2006

ApJ

126

135

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“…The importance of the Rayleigh-Taylor (RT) instability and turbulence in accelerating a thermonuclear flame in Type Ia supernovae (SNe Ia) is well recognized (Müller & Arnett 1982;Livne 1993;Khokhlov 1995;Niemeyer & Hillebrandt 1995;Gamezo et al 2003;Reinecke et al 2002). Nevertheless, the physics of reactive flame instabilities in SNe Ia is still not completely understood.…”

Section: Introductionmentioning

confidence: 99%

Three‐dimensional Numerical Simulations of Rayleigh‐Taylor Unstable Flames in Type Ia Supernovae

Zingale

Woosley

Rendleman

et al. 2005

ApJ

129

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Flame instabilities play a dominant role in accelerating the burning front to a large fraction of the speed of sound in a Type Ia supernova. We present a three-dimensional numerical simulation of a Rayleigh-Taylor unstable carbon flame, following its evolution through the transition to turbulence. A low-Mach number hydrodynamics method is used, freeing us from the harsh time step restrictions imposed by sound waves. We fully resolve the thermal structure of the flame and its reaction zone, eliminating the need for a flame model. A single density is considered, 1:5 ; 10 7 g cm À3 , and half-carbon, half-oxygen fuel: conditions under which the flame propagated in the flamelet regime in our related two-dimensional study. We compare to a corresponding two-dimensional simulation and show that while fire polishing keeps the small features suppressed in two dimensions, turbulence wrinkles the flame on far smaller scales in the three-dimensional case, suggesting that the transition to the distributed burning regime occurs at higher densities in three dimensions. Detailed turbulence diagnostics are provided. We show that the turbulence follows a Kolmogorov spectrum and is highly anisotropic on the large scales, with a much larger integral scale in the direction of gravity. Furthermore, we demonstrate that it becomes more isotropic as it cascades down to small scales. On the basis of the turbulent statistics and the flame properties of our simulation, we compute the Gibson scale. We show the progress of the turbulent flame through a classic combustion regime diagram, indicating that the flame just enters the distributed burning regime near the end of our simulation.

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“…Even a turbulence-boosted flame is relatively slow so that it may not lead to a sufficient fuel consumption before fuel densities drop below the burning threshold ( < ∼ 10 7 g cm −3 ). Although turbulent deflagration models (Reinecke et al 2002b;Gamezo et al 2003;Röpke & Hillebrandt 2005a;Röpke et al 2006; reproduce the observational features of weak SN Ia explosions (Blinnikov et al 2006), there exist open questions (Kozma et al 2005) and presently it seems that they cannot account for the more energetic events. This issue certainly needs more exploration (in particular the buoyancy induced turbulence effects at the high Reynolds numbers of ∼10 14 expected in SNe Ia, see Cabot & Cook 2006) but it may also be interpreted as an incompleteness of such models.…”

Section: Introductionmentioning

confidence: 99%

Delayed detonations in full-star models of type Ia supernova explosions

Röpke

Niemeyer

2006

A&A

134

158

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Aims. We present the first full-star three-dimensional explosion simulations of thermonuclear supernovae including parameterized deflagration-to-detonation transitions that occur once the flame enters the distributed burning regime. Methods. Treating the propagation of both the deflagration and the detonation waves in a common front-tracking approach, the detonation is prevented from crossing ash regions. Results. Our criterion triggers the detonation wave at the outer edge of the deflagration flame and consequently it has to sweep around the complex structure and to compete with expansion. Despite the impeded detonation propagation, the obtained explosions show reasonable agreement with global quantities of observed type Ia supernovae. By igniting the flame in different numbers of kernels around the center of the exploding white dwarf, we set up three different models shifting the emphasis from the deflagration phase to the detonation phase. The resulting explosion energies and iron group element productions cover a large part of the diversity of type Ia supernovae. Conclusions. Flame-driven deflagration-to-detonation transitions, if hypothetical, remain a possibility deserving further investigation.

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Thermonuclear Supernovae: Simulations of the Deflagration Stage and Their Implications

Cited by 358 publications

References 50 publications

Low Mach Number Modeling of Type Ia Supernovae. I. Hydrodynamics

Low Mach Number Modeling of Type Ia Supernovae. I. Hydrodynamics

Three‐dimensional Numerical Simulations of Rayleigh‐Taylor Unstable Flames in Type Ia Supernovae

Delayed detonations in full-star models of type Ia supernova explosions

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