From 563fb6618a8cc1ecdefa000d1ec7f2a746bdab2c Mon Sep 17 00:00:00 2001 From: "Jean M. Sexton" Date: Fri, 12 Feb 2021 17:14:35 -0800 Subject: [PATCH] Minor paper rearrangement --- Docs/paper/paper.md | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/Docs/paper/paper.md b/Docs/paper/paper.md index a371b5c5..37d0306b 100644 --- a/Docs/paper/paper.md +++ b/Docs/paper/paper.md @@ -50,7 +50,7 @@ astrophysical simulation codes. The core hydrodynamics solver in Nyx [@nyx-paper1] is based on the directionally unsplit corner transport upwind method of @ctu with piecewise parabolic reconstruction [@ppm]. In Nyx, we have -several modes of coupling the stiff heating-cooling terms to the hydro. +several modes of coupling the stiff heating-cooling source terms to the hydro. The simplest method is the traditional operator splitting approach, using Strang splitting to achieve second-order in time. However, this coupling can break down, and we have an alternative to Strang splitting @@ -60,26 +60,27 @@ The simplified SDC method uses the CTU PPM hydro together with an iterative scheme to fully couple the source terms and hydro, still to second order [@simple_sdc]. -The evolution of baryonic gas coupled with an N-body treatment of the dark -matter in an expanding universe. The mesh-based hydrodynamical baryonic gas -evolution is coupled through gravity to the particle-based representation of -dark matter. The dark matter particles are moved with a move-kick-drift algorithm -[@movekickdrift]. The Poisson equation for self-gravity of the baryonic gas and dark -matter is solved using geometric multigrid method. Nyx simulations can optionally -model neutrino particle effects and active galactic nuclei feedback. - -Nyx has a set of additional physics necessary to model the intergalactic medium. +Nyx has a set of additional physics necessary to model the intergalactic medium +using heating-cooling source terms. The code follows the abundance of six species: neutral andionized hydrogen, neutral, once and twice ionized helium, and free electrons. For these species, all relevant atomic processes - ionization, recombination, and free-free transitions are -modeled in the code. Heating and cooling are calculated using sub-cycled approach -in order to avoid running whole code on ashort, cooling timescale. +modeled in the code. Heating and cooling source terms are calculated using +a sub-cycled approach in order to avoid running the whole code on a short, cooling timescale. Cosmological reionization is accounted for via a spatially uniform, but time-varying ultraviolet background (UVB) radiation field, inputed to the code as a list of photoionization and photoheating -rates that vary with redshift, but we also have capability to model flash reionization +rates that vary with redshift. Nyx also has the capability to model flash reionization as well as inhomogeneous reionization [@onorbe2019]. +The evolution of baryonic gas is coupled with an N-body treatment of the dark +matter in an expanding universe. The mesh-based hydrodynamical baryonic gas +evolution is coupled through gravity to the particle-based representation of +dark matter. The dark matter particles are moved with a move-kick-drift algorithm +[@movekickdrift]. The Poisson equation for self-gravity of the baryonic gas and dark +matter is solved using geometric multigrid method. Nyx simulations can optionally +model neutrino particle effects and active galactic nuclei feedback. + Nyx is built on the AMReX [@AMReX] adaptive mesh refinement (AMR) library and is written in C++. AMR levels are advanced at their own timestep (subcycling)