TY - JOUR
T1 - An Extension of the Athena++ Framework for General Equations of State
AU - Coleman, Matthew S.B.
N1 - Publisher Copyright:
© 2020. The American Astronomical Society. All rights reserved.
PY - 2020/5
Y1 - 2020/5
N2 - We present modifications to the Athena++ framework to enable the use of general equations of state (EOS). A part of our motivation for doing so is to model transient astrophysics phenomena, as these types of events are often not well approximated by an ideal gas. This necessitated changes to the Riemann solvers implemented in Athena++. We discuss the adjustments made to the Harten-Lax-van Leer-Contact and Harten-Lax-van Leer-Discontinuities solvers and EOS calls required for arbitrary EOS. We demonstrate the reliability of our code in a number of tests that utilize a relatively simple, but nontrivial, EOS based on hydrogen ionization, appropriate for the transition from atomic to ionized hydrogen. Additionally, we perform tests using an electron-positron Helmholtz EOS, appropriate for regimes where nuclear statistical equilibrium is a good approximation. These new complex EOS tests overall show that our modifications to Athena++ accurately solve the Riemann problem with linear convergence and linear wave tests with quadratic convergence. We provide our test solutions as a means to check the accuracy of other hydrodynamic codes. Our tests and additions to Athena++ will enable further research into (magneto)hydrodynamic problems where realistic treatments of the EOS are required.
AB - We present modifications to the Athena++ framework to enable the use of general equations of state (EOS). A part of our motivation for doing so is to model transient astrophysics phenomena, as these types of events are often not well approximated by an ideal gas. This necessitated changes to the Riemann solvers implemented in Athena++. We discuss the adjustments made to the Harten-Lax-van Leer-Contact and Harten-Lax-van Leer-Discontinuities solvers and EOS calls required for arbitrary EOS. We demonstrate the reliability of our code in a number of tests that utilize a relatively simple, but nontrivial, EOS based on hydrogen ionization, appropriate for the transition from atomic to ionized hydrogen. Additionally, we perform tests using an electron-positron Helmholtz EOS, appropriate for regimes where nuclear statistical equilibrium is a good approximation. These new complex EOS tests overall show that our modifications to Athena++ accurately solve the Riemann problem with linear convergence and linear wave tests with quadratic convergence. We provide our test solutions as a means to check the accuracy of other hydrodynamic codes. Our tests and additions to Athena++ will enable further research into (magneto)hydrodynamic problems where realistic treatments of the EOS are required.
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U2 - 10.3847/1538-4365/ab82ff
DO - 10.3847/1538-4365/ab82ff
M3 - Article
AN - SCOPUS:85087213987
SN - 0067-0049
VL - 248
JO - Astrophysical Journal, Supplement Series
JF - Astrophysical Journal, Supplement Series
IS - 1
M1 - 7
ER -