An electron-positron equation of state based on table interpolation the Helmholtz free energy is developed and analyzed. The scheme guarantees perfect thermodynamic consistency, independent interpolating function. choice a biquintic Hermite polynomial as function results in accurately reproducing underlying data table, yields derivatives pressure, specific entropy, internal which are smooth continuous. execution speed—evaluated across several different machine architectures, compiler...

view Abstract Citations (90) References (57) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The QCD Phase Transition and Supernova Core Collapse Gentile, N. A. ; Aufderheide, M. B. Mathews, G. J. Swesty, F. D. Fuller, We examine the implications for stellar core collapse of a phase transition occurring at densities few times nuclear matter density. use schematic equation state motivated by Skyrme model low-energy approximation to QCD, which contains...

view Abstract Citations (86) References (30) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Role of the Equation State in ``Prompt'' Phase Type II Supernovae Swesty, F. Douglas ; Lattimer, James M. Myra, Eric S. We examine role equation state (EOS) hot, dense matter prompt phase stellar collapse. In order to achieve this goal, we have carried out radiation hydrodynamic simulations using an adjustable EOS that is consistent with constraints placed on by...

It is now generally agreed that multidimensional, multigroup, neutrino-radiation hydrodynamics (RHD) an indispensable element of any realistic model stellar-core collapse, core-collapse supernovae, and proto-neutron star instabilities. We have developed a new, two-dimensional, multigroup algorithm can neutrino-RHD flows in supernovae. Our uses approach similar to the ZEUS family algorithms, originally by Stone Norman. However, this completely new implementation extends previous work three...

The Type Ia supernova progenitor problem is one of the most perplexing and exciting problems in astrophysics, requiring detailed numerical modeling to complement observations these explosions. One possible that has merited recent theoretical attention white dwarf merger scenario, which potential naturally explain many observed characteristics supernovae. To date there have been relatively few self-consistent simulations merging systems using mesh-based hydrodynamics. This first paper a...

Flux-limited diffusion has become a popular method for treating radiation transport in multidimensional astrophysical simulation codes with multi-group flux-limited (MGFLD) undergoing increasing use number of applications. The most computationally demanding aspect this technique is the solution large linear systems that arise from implicit finite-difference scheme used to solve underlying integro-PDEs describe MGFLD. these often dominates computational cost carrying out simulations. Hence,...

The numerical modeling of binary neutron star mergers has become a subject much interest in recent years. While full and accurate model this phenomenon would require the evolution equations relativistic hydrodynamics along with Einstein field equations, qualitative study early stages on inspiral can be accomplished by either Newtonian or post-Newtonian models, which are more tractable. However, even purely models present challenges that must overcome order to have inspiral. In particular,...

We present early results from a study addressing the question of how one treats propagation incertitude, that is, epistemic uncertainty, in input parameters astrophysical simulations. As an example, we look at incertitude control for stellar winds MESA evolution apply two methods propagation, Cauchy Deviates method and Quadratic Response Surface method, to quantify output uncertainty final white dwarf mass given range values wind parameters. The methodology is applicable problem propagating...

Understanding the explosion mechanism of core collapse supernovae is a problem that has plagued nuclear astrophysicists since first computational models this phenomenon were carried out in 1960s. Our current theories violent center around multi-dimensional effects involving radiation-hydrodynamic flows hot, dense matter and neutrinos. Modeling these radiative presents challenge will continue to stress high-performance computing beyond teraflop petaflop level. In paper we describe few...

This paper describes an implicit approach and nonlinear solver for solution of radiation-hydrodynamic problems in the context supernovae proto-neutron star cooling. The robust applies Newton-Krylov methods overcomes difficulties discontinuous limiters discretized equations scaling over wide ranges physical behavior. We discuss these difficulties, our overcoming them, numerical results demonstrating accuracy efficiency method.

view Abstract Citations (12) References (30) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Implicit General Relativistic Hydrodynamic Methods for Modeling the Late-Time Explosion Mechanism in Core Collapse Supernovae Swesty, F. Douglas One of difficulties numerically modeling supernovae is great disparity timescales present phenomena. The late-time explosion mechanism thought to take place on seconds while Courant-Friedrichs-Lewy (CFL) stability timescale...

Abstract We present a look at Ookami, project providing community access to testbed supercomputer with the ARM-based A64FX processors developed by collaboration between RIKEN and Fujitsu deployed in Japanese Fugaku. provide an overview of details hardware, describe user base education/training program. highlights from previous performance studies two astrophysical simulation codes strong scaling study full 3D supernova as example machine’s capability.

We present results of a performance study an astrophysical radiation hydrodynamics code, V2D, on the Arm-based A64FX processor developed by Fujitsu. The code solves sparse linear systems, task for which architecture should be well suited. performed analysis Ookami, Apollo 80 platform utilizing processor. explored several compilers and anal-ysis packages found did not perform as expected under scalable vector extension optimization, suggesting that "deeper dive" into analyzing is worthwhile....

We discuss recent advances in the radiative-hydrodynamic modeling of core collapse supernovae multi-dimensions. A number earlier attempts at fully radiation-hydrodynamic models utilized either grey approximation to describe neutrino distribution or more sophisticated multigroup transport methods restricted radial rays. In both cases these have also neglected O(v/c) terms that couple radiation and matter strongly optically thick regions collapsed core. this paper we present some resolve...

The fields of radiation and hydrodynamics are time-honored disciplines in physics. However, it is only since the nuclear age that importance - a single field studying interplay material together has come into prominence. Similarly, computer physically interesting problems this have become tractable. In article, authors discuss process building model to study one fundamental astrophysics: supernova explosion massive star caused by collapse its core. An explanation for mechanism involves...

We present a look at Ookami, project providing community access to testbed supercomputer with the ARM-based A64FX processors developed by collaboration between RIKEN and Fujitsu deployed in Japanese Fugaku. describe project, provide details about user base education/training program, highlights from performance studies of two astrophysical simulation codes.