A DG-IMEX method for two-moment neutrino transport: Nonlinear solvers for neutrino-matter coupling
| Autor: | M. Paul Laiu, Ran Chu, O. E. Bronson Messer, J. Austin Harris, Eirik Endeve |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
High Energy Astrophysical Phenomena (astro-ph.HE)
Physics Discretization Astrophysics::High Energy Astrophysical Phenomena FOS: Physical sciences Relaxation (iterative method) Astronomy and Astrophysics Context (language use) 010103 numerical & computational mathematics Solver 01 natural sciences Lepton number Nonlinear system Space and Planetary Science Discontinuous Galerkin method 0103 physical sciences Statistical physics 0101 mathematics Neutrino Astrophysics - High Energy Astrophysical Phenomena 010303 astronomy & astrophysics |
| Popis: | Neutrino-matter interactions play an important role in core-collapse supernova (CCSN) explosions as they contribute to both lepton number and/or four-momentum exchange between neutrinos and matter, and thus act as the agent for neutrino-driven explosions. Due to the multiscale nature of neutrino transport in CCSN simulations, an implicit treatment of neutrino-matter interactions is desired, which requires solutions of coupled nonlinear systems in each step of the time integration scheme. In this paper we design and compare nonlinear iterative solvers for implicit systems with energy coupling neutrino-matter interactions commonly used in CCSN simulations. Specifically, we consider electron neutrinos and antineutrinos, which interact with static matter configurations through the Bruenn~85 opacity set. The implicit systems arise from the discretization of a non-relativistic two-moment model for neutrino transport, which employs the discontinuous Galerkin (DG) method for phase-space discretization and an implicit-explicit (IMEX) time integration scheme. In the context of this DG-IMEX scheme, we propose two approaches to formulate the nonlinear systems -- a coupled approach and a nested approach. For each approach, the resulting systems are solved with Anderson-accelerated fixed-point iteration and Newton's method. The performance of these four iterative solvers has been compared on relaxation problems with various degree of collisionality, as well as proto-neutron star deleptonization problems with several matter profiles adopted from spherically symmetric CCSN simulations. Numerical results suggest that the nested Anderson-accelerated fixed-point solver is more efficient than other tested solvers for solving implicit nonlinear systems with energy coupling neutrino-matter interactions. This paper has been accepted for publication in ApJS |
| Databáze: | OpenAIRE |
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