A numerical model for multigroup radiation hydrodynamics

Vaytet, N.; Audit, E.; Dubroca, Bruno; Delahaye, F.

doi:10.1016/j.jqsrt.2011.01.027

Cited by 77 publications

(79 citation statements)

References 23 publications

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“…This code is described in detail in an upcoming paper (in preparation). For the purposes of this paper, we note that it employs spherical coordinates in one and two spatial dimensions, solves the comoving-frame, multigroup, two-moment, velocity-dependent transport equations to O(v/c), and uses the M1 tensor closure for the second and third moments of the radiation fields (Dubroca and Feugeas 1999;Vaytet et al 2011). Three species of neutrino (ν e ,ν e , and "ν μ " [ν μ ,ν μ , ν τ , andν τ lumped together]) are followed using an explicit Godunov characteristic method applied to the radiation transport operators, but an implicit solver for the radiation source terms.…”

Section: Numerical Methods and Computational Setupmentioning

confidence: 99%

Crucial Physical Dependencies of the Core-Collapse Supernova Mechanism

et al. 2018

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We explore with self-consistent 2D FORNAX simulations the dependence of the outcome of collapse on many-body corrections to neutrino-nucleon cross sections, the nucleon-nucleon bremsstrahlung rate, electron capture on heavy nuclei, pre-collapse seed perturbations, and inelastic neutrino-electron and neutrino-nucleon scattering. Importantly, proximity to criticality amplifies the role of even small changes in the neutrino-matter couplings, and such changes can together add to produce outsized effects. When close to the critical condition the cumulative result of a few small effects (including seeds) that individually have only modest consequence can convert an anemic into a robust explosion, or even a dud into a blast. Such sensitivity is not seen in one dimension and may explain the apparent heterogeneity in the outcomes of detailed simulations performed internationally. A natural conclusion is that the different groups collectively are closer to a realistic understanding of the mechanism of core-collapse supernovae than might have seemed apparent. Supernovae Edited by

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Section: Numerical Methods and Computational Setupmentioning

confidence: 99%

Crucial Physical Dependencies of the Core-Collapse Supernova Mechanism

et al. 2018

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“…HERACLES is a Eulerian multi-dimensional radiationhydrodynamics code (González et al 2007), with the possibility for multi-group radiation transport (Vaytet et al 2011). The hydrodynamics is treated using a standard second order Godunov scheme.…”

Section: Numerical Approachmentioning

confidence: 99%

“…The effect of scattering in regions where the scattering opacity is dominant can then be taken into account. Finally, the radiative transfer is formulated in the co-moving frame and as is shown in Vaytet et al (2011) the Doppler and aberrations effects are properly accounted for, which is important when large velocity gradients are present.…”

Section: Numerical Approachmentioning

confidence: 99%

Numerical simulations of superluminous supernovae of type IIn

Dessart¹,

Audit²,

Hillier³

2015

Monthly Notices of the Royal Astronomical Society

116

172

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We present numerical simulations that include 1-D Eulerian multi-group radiationhydrodynamics, 1-D non-Local-Thermodynamic-Equilibrium (non-LTE) radiative transfer, and 2-D polarised radiative transfer for super-luminous interacting supernovae (SNe). Our reference model is a ∼10 M ⊙ inner shell with 10 51 erg ramming into a ∼3 M ⊙ cold outer shell (the circumstellar-medium, or CSM) that extends from 10 15 to 2×10 16 cm and moves at 100 km s −1 . We discuss the light curve evolution, which cannot be captured adequately with a grey approach. In these interactions, the shock-crossing time through the optically-thick CSM is much longer than the photon diffusion time. Radiation is thus continuously leaking from the shock through the CSM, in disagreement with the shell-shocked model that is often invoked. Our spectra redden with time, with a peak distribution in the near-UV during the first month gradually shifting to the optical range over the following year. Initially Balmer lines exhibit a narrow line core and the broad line wings that are characteristic of electron scattering in the SNe IIn atmospheres (CSM). At later times they also exhibit a broad blue shifted component which arises from the cold dense shell. Our model results are broadly consistent with the bolometric light curve and spectral evolution observed for SN 2010jl. Invoking a prolate pole-to-equator density ratio in the CSM, we can also reproduce the ∼2% continuum polarisation, and line depolarisation, observed in SN 2010jl. By varying the inner shell kinetic energy and the mass and extent of the outer shell, a large range of peak luminosities and durations, broadly compatible with super-luminous SNe IIn like 2010jl or 2006gy, can be produced.

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“…After core bounce, the fastest hydrodynamic signal speeds in the core-collapse supernova problem are within a factor of a few of the speed of light, so a timeexplicit integration of the non-stiff transport terms is not only simpler and generally more accurate, it is also faster than globally coupled time-implicit transport solvers that are typically employed in radiation hydrodynamics methods. Radiation quantities are reconstructed with linear profiles and the resulting edge states are used to calculate fluxes via the HLLE solver, similar to Vaytet et al (2011). As in O' Connor & Ott (2013), the HLLE fluxes are corrected to reduce numerical diffusion in the non-hyperbolic regime.…”

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confidence: 99%

Should One Use the Ray-by-Ray Approximation in Core-Collapse Supernova Simulations?

Skinner

Burrows

Dolence

2016

ApJ

102

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We perform the first self-consistent, time-dependent, multi-group calculations in two dimensions (2D) to address the consequences of using the ray-by-ray+ transport simplification in core-collapse supernova simulations. Such a dimensional reduction is employed by many researchers to facilitate their resource-intensive calculations. Our new code (Fornax) implements multi-D transport, and can, by zeroing out transverse flux terms, emulate the ray-by-ray+ scheme. Using the same microphysics, initial models, resolution, and code, we compare the results of simulating 12-, 15-, 20-, and 25-M ⊙ progenitor models using these two transport methods. Our findings call into question the wisdom of the pervasive use of the ray-by-ray+ approach. Employing it leads to maximum post-bounce/preexplosion shock radii that are almost universally larger by tens of kilometers than those derived using the more accurate scheme, typically leaving the post-bounce matter less bound and artificially more "explodable." In fact, for our 25-M ⊙ progenitor, the ray-by-ray+ model explodes, while the corresponding multi-D transport model does not. Therefore, in two dimensions the combination of ray-by-ray+ with the axial sloshing hydrodynamics that is a feature of 2D supernova dynamics can result in quantitatively, and perhaps qualitatively, incorrect results.

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A numerical model for multigroup radiation hydrodynamics

Cited by 77 publications

References 23 publications

Crucial Physical Dependencies of the Core-Collapse Supernova Mechanism

Crucial Physical Dependencies of the Core-Collapse Supernova Mechanism

Numerical simulations of superluminous supernovae of type IIn

Should One Use the Ray-by-Ray Approximation in Core-Collapse Supernova Simulations?

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