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Title: A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae

The mechanism driving core-collapse supernovae is sensitive to the interplay between matter and neutrino radiation. However, neutrino radiation transport is very difficult to simulate, and several radiation transport methods of varying levels of approximation are available. In this paper, we carefully compare for the first time in multiple spatial dimensions the discrete ordinates (DO) code of Nagakura, Yamada, and Sumiyoshi and the Monte Carlo (MC) code Sedonu, under the assumptions of a static fluid background, flat spacetime, elastic scattering, and full special relativity. We find remarkably good agreement in all spectral, angular, and fluid interaction quantities, lending confidence to both methods. The DO method excels in determining the heating and cooling rates in the optically thick region. The MC method predicts sharper angular features due to the effectively infinite angular resolution, but struggles to drive down noise in quantities where subtractive cancellation is prevalent, such as the net gain in the protoneutron star and off-diagonal components of the Eddington tensor. We also find that errors in the angular moments of the distribution functions induced by neglecting velocity dependence are subdominant to those from limited momentum-space resolution. We briefly compare directly computed second angular moments to those predicted by popular algebraicmore » two-moment closures, and we find that the errors from the approximate closures are comparable to the difference between the DO and MC methods. Finally, included in this work is an improved Sedonu code, which now implements a fully special relativistic, time-independent version of the grid-agnostic MC random walk approximation.« less
Authors:
ORCiD logo [1] ; ORCiD logo [1] ; ORCiD logo [2] ;  [3] ; ORCiD logo [4] ; ORCiD logo [5]
  1. California Inst. of Technology (CalTech), Pasadena, CA (United States). Theoretical AstroPhysics Including Relativity and Cosmology (TAPIR). Walter Burke Inst. for Theoretical Physics
  2. California Inst. of Technology (CalTech), Pasadena, CA (United States). Theoretical AstroPhysics Including Relativity and Cosmology (TAPIR). Walter Burke Inst. for Theoretical Physics; Kyoto Univ. (Japan). Center for Gravitational Physics and International Research Unit of Advanced Future Studies. Yukawa Inst. for Theoretical Physics
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Numazu College of Technology (Japan)
  5. Waseda Univ., Tokyo (Japan). Advanced Research Inst. for Science & Engineering. Dept. of Science and Engineering
Publication Date:
Report Number(s):
LA-UR-17-24929
Journal ID: ISSN 1538-4357; TRN: US1800801
Grant/Contract Number:
AC52-06NA25396; OCI-0725070; ACI-1238993; TG-PHY100033; ACI-1440083; TCAN AST-1333520; CAREER PHY-1151197; PHY-1404569; 27-348; 15K05093; 16H03986; 26104006
Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 847; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States); California Inst. of Technology (CalTech), Pasadena, CA (United States); Waseda Univ., Tokyo (Japan); Kyoto Univ. (Japan)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA); LANL Laboratory Directed Research and Development (LDRD) Program; National Science Foundation (NSF); State of Illinois (United States); Japan Society for the Promotion of Science (JSPS); Ministry of Education, Culture, Sports, Science, and Technology (MEXT) (Japan)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; neutrinos; radiative transfer; supernovae
OSTI Identifier:
1415403

Richers, Sherwood, Nagakura, Hiroki, Ott, Christian D., Dolence, Joshua, Sumiyoshi, Kohsuke, and Yamada, Shoichi. A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae. United States: N. p., Web. doi:10.3847/1538-4357/aa8bb2.
Richers, Sherwood, Nagakura, Hiroki, Ott, Christian D., Dolence, Joshua, Sumiyoshi, Kohsuke, & Yamada, Shoichi. A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae. United States. doi:10.3847/1538-4357/aa8bb2.
Richers, Sherwood, Nagakura, Hiroki, Ott, Christian D., Dolence, Joshua, Sumiyoshi, Kohsuke, and Yamada, Shoichi. 2017. "A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae". United States. doi:10.3847/1538-4357/aa8bb2. https://www.osti.gov/servlets/purl/1415403.
@article{osti_1415403,
title = {A Detailed Comparison of Multidimensional Boltzmann Neutrino Transport Methods in Core-collapse Supernovae},
author = {Richers, Sherwood and Nagakura, Hiroki and Ott, Christian D. and Dolence, Joshua and Sumiyoshi, Kohsuke and Yamada, Shoichi},
abstractNote = {The mechanism driving core-collapse supernovae is sensitive to the interplay between matter and neutrino radiation. However, neutrino radiation transport is very difficult to simulate, and several radiation transport methods of varying levels of approximation are available. In this paper, we carefully compare for the first time in multiple spatial dimensions the discrete ordinates (DO) code of Nagakura, Yamada, and Sumiyoshi and the Monte Carlo (MC) code Sedonu, under the assumptions of a static fluid background, flat spacetime, elastic scattering, and full special relativity. We find remarkably good agreement in all spectral, angular, and fluid interaction quantities, lending confidence to both methods. The DO method excels in determining the heating and cooling rates in the optically thick region. The MC method predicts sharper angular features due to the effectively infinite angular resolution, but struggles to drive down noise in quantities where subtractive cancellation is prevalent, such as the net gain in the protoneutron star and off-diagonal components of the Eddington tensor. We also find that errors in the angular moments of the distribution functions induced by neglecting velocity dependence are subdominant to those from limited momentum-space resolution. We briefly compare directly computed second angular moments to those predicted by popular algebraic two-moment closures, and we find that the errors from the approximate closures are comparable to the difference between the DO and MC methods. Finally, included in this work is an improved Sedonu code, which now implements a fully special relativistic, time-independent version of the grid-agnostic MC random walk approximation.},
doi = {10.3847/1538-4357/aa8bb2},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 847,
place = {United States},
year = {2017},
month = {10}
}