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We present the new code ALCAR developed to model multidimensional, multi energy-group neutrino transport in the context of supernovae and neutron-star mergers. The algorithm solves the evolution equations of the 0th- and 1st-order angular…

高能天体物理现象 · 物理学 2015-09-09 Oliver Just , Martin Obergaulinger , H. -Thomas Janka

$\underline{\textbf{MO}}$nte-carlo $\underline{\textbf{N}}$ucleon transport $\underline{\textbf{C}}$ode (MONC) for nucleon transport is being developed for several years. Constructive Solid Geometry concept is applied with the help of solid…

核理论 · 物理学 2020-08-27 H. Kumawat , P. P. K. Venkata

The derivation of the multi-temperature generalized Zhdanov closure is provided starting from the most general form of the left hand side of the moment averaged kinetic equation with the Sonine-Hermite polynomial ansatz for an arbitrary…

We perform global three-dimensional simulations of accretion disks integrating the compressible, non-viscous, but diffusive MHD equations. The disk is supposed to be isothermal. We make use of the ZEUS-3D code integrating the MHD equations…

天体物理学 · 物理学 2009-11-06 R. Arlt , G. Rudiger

We derive conservative, multidimensional, energy-dependent moment equations for neutrino transport in core-collapse supernovae and related astrophysical systems, with particular attention to the consistency of conservative four-momentum and…

太阳与恒星天体物理 · 物理学 2012-12-18 Eirik Endeve , Christian Y. Cardall , Anthony Mezzacappa

In this work we present two new closures for the spherical harmonics (PN) method in slab geometry transport problems. Our approach begins with an analysis of the squared-residual of the transport equation where we show that the standard…

计算物理 · 物理学 2016-05-20 Weixiong Zheng , Ryan G. McClarren

We investigate neutrino-driven convection in core collapse supernovae and its ramifications for the explosion mechanism, for a 15 solar mass model. Our two-dimensional simulation begins at 12 ms after bounce and proceeds for 500 ms. We…

天体物理学 · 物理学 2009-10-30 A. Mezzacappa , A. C. Calder , S. W. Bruenn , J. M. Blondin , M. W. Guidry , M. R. Strayer , A. S. Umar

Considering general relativistic, two-dimensional (2D) supernova (SN) explosion models of progenitor stars between 8.1 and 27 solar masses, we systematically analyze the properties of the neutrino emission from core collapse and bounce to…

太阳与恒星天体物理 · 物理学 2014-06-27 B. Müller , H. -Th. Janka

We trained deep neural networks (DNNs) as a function of the neutrino energy density, flux, and the fluid velocity to reproduce the Eddington tensor for neutrinos obtained in our first-principles core-collapse supernova (CCSN) simulations.…

高能天体物理现象 · 物理学 2022-02-09 Akira Harada , Shota Nishikawa , Shoichi Yamada

Due to the Helium-3 crisis, alternatives to the standard neutron detection techniques are becoming urgent. In addition, the instruments of the European Spallation Source (ESS) require advances in the state of the art of neutron detection.…

Modeling correctly the transport of neutrinos is crucial in some astrophysical scenarios such as core-collapse supernovae and binary neutron star mergers. In this paper, we focus on the truncated-moment formalism, considering only the first…

广义相对论与量子宇宙学 · 物理学 2023-05-30 Manuel R. Izquierdo , Lorenzo Pareschi , Borja Miñano , Joan Massó , Carlos Palenzuela

High-order moving-mesh methods can effectively reduce numerical diffusion, but their formal accuracy typically relies on the regularity of the mesh velocity. This dependency creates a fundamental conflict in the numerical solution of…

数值分析 · 数学 2026-02-11 Chaoyi Cai , Qiqin Cheng , Di Wu , Jianxian Qiu

Time-dependent electromagnetic signatures from core-collapse supernovae are the result of detailed transport of the shock-deposited and radioactively-powered radiation through the stellar ejecta. Due to the complexity of the underlying…

高能天体物理现象 · 物理学 2020-07-29 Benny T. -H. Tsang , Jared A. Goldberg , Lars Bildsten , Daniel Kasen

We present the implementation of general-relativistic resistive magnetohydrodynamics solvers and three divergence-free handling approaches adopted in the General-relativistic multigrid numerical (Gmunu) code. In particular,…

天体物理仪器与方法 · 物理学 2022-07-27 Patrick Chi-Kit Cheong , David Yat Tung Pong , Anson Ka Long Yip , Tjonnie Guang Feng Li

Momentum spectra of hydrogen isotopes have been measured at 3.5 deg from C12 fragmentation on a Be target. Momentum spectra cover both the region of fragmentation maximum and the cumulative region. Differential cross sections span five…

The method of moments is widely used for the reduction of kinetic equations into fluid models. It consists in extracting the moments of the kinetic equation with respect to a velocity variable, but the resulting system is a priori…

计算物理 · 物理学 2023-04-05 Michael R. A. Abdelmalik , Zhenning Cai , Teddy Pichard

We develop a numerical scheme and code for estimating the energy and momentum transfer via neutrino pair annihilation ($\nu + {\bar \nu} \to e^{-}+ e^{+}$), bearing in mind the application to the collapsar models of gamma-ray bursts (GRBs).…

高能天体物理现象 · 物理学 2014-11-20 Seiji Harikae , Kei Kotake , Tomoya Takiwaki

The powerful high-energy phenomena typically encountered in astrophysics invariably involve physical engines, like neutron stars and black hole accretion disks, characterized by a combination of highly magnetized plasmas, strong…

高能天体物理现象 · 物理学 2015-06-05 N. Bucciantini , L. Del Zanna

One of the key problems in tensor completion is the number of uniformly random sample entries required for recovery guarantee. The main aim of this paper is to study $n_1 \times n_2 \times n_3$ third-order tensor completion based on…

机器学习 · 统计学 2022-01-25 Guang-Jing Song , Michael K. Ng , Xiongjun Zhang

In CANDECOMP/PARAFAC tensor decomposition, degeneracy often occurs in some difficult scenarios, e.g., when the rank exceeds the tensor dimension, or when the loading components are highly collinear in several or all modes, or when CPD does…

数值分析 · 计算机科学 2017-09-26 Anh-Huy Phan , Petr Tichavský , Andrzej Cichocki