Chimera: A massively parallel code for core-collapse supernova simulation

TL;DR

Chimera is a comprehensive, parallel simulation code for modeling core-collapse supernovae, integrating detailed physics like neutrino transport, hydrodynamics, and nuclear reactions to study explosion mechanisms and observable signals.

Contribution

This paper presents the detailed design and current version of Chimera, a novel multi-physics, parallel code for simulating core-collapse supernovae with high fidelity.

Findings

Enables detailed study of neutrino effects in supernova explosions

Simulates multi-dimensional hydrodynamics with realistic physics

Predicts observable signatures like neutrino signals and gravitational waves

Abstract

We provide a detailed description of the Chimera code, a code developed to model core collapse supernovae in multiple spatial dimensions. The core collapse supernova explosion mechanism remains the subject of intense research. Progress to date demonstrates that it involves a complex interplay of neutrino production, transport, and interaction in the stellar core, three-dimensional stellar core fluid dynamics and its associated instabilities, nuclear burning, and the foundational physics of the neutrino-stellar core weak interactions and the equations of state of all stellar core constituents -particularly, the nuclear equation of state associated with nucleons, both free and bound in nuclei. Chimera, by incorporating detailed neutrino transport, realistic neutrino-matter interactions, three-dimensional hydrodynamics, realistic nuclear, leptonic, and photonic equations of state, and a nuclear reaction network, along with other refinements, can be used to study the role of neutrino radiation, hydrodynamic instabilities, and a variety of input physics in the explosion mechanism itself. It can also be used to compute observables such as neutrino signatures, gravitational radiation, and the products of nucleosynthesis associated with core collapse supernovae. The code contains modules for neutrino transport, multidimensional compressible hydrodynamics, nuclear reactions, a variety of neutrino interactions, equations of state, and modules to provide data for post-processing observables such as the products of nucleosynthesis, and gravitational radiation. Chimera is an evolving code, being updated periodically with improved input physics and numerical refinements. We detail here the current version of the code, from which future improvements will stem, which can in turn be described as needed in future publications.