Posts for the month of December 2021

CE EOS Simulations

Computing

  • Allocation on Frontera ends on Dec. 31 — update?
  • Parallel HDF5 (currently only being used for post-processing)
    • Bug has been identified and debugging ongoing (Jonathan)

Energy conservation

  • Tested new poisson.f90 designed to explicitly conserve energy (though not yet including particles), as in Jiang+13.
    • Used low resolution CE run with periodic boundary conditions (so that flux of energy through boundaries does not change total energy in domain)
    • Found that energy conservation is worse than with the original poisson.f90, not better.
      • This means that there is a bug in the new poisson.f90 (could it be something obvious?)

EOS Runs

  • Computed volume integrated mass and released energy for Run 271, using Python, plotted, and made pdf file. Includes only 3 frames (frame 0, 100 and 200).

Runs for the paper

The plan is to compare 3 runs which are identical except for the EOS:

  • Run 277: MESA EOS (completed up to frame 170 and will go as far as energy conservation allows, maybe frame 300
  • Run 282: Ideal gas gamma=5/3 EOS (completed up to frame 33 and will go up to frame ~300).
  • Run 283: MESA EOS with recombination energy removed from EOS tables (not yet started, will go up to frame ~300)

We are also doing a high resolution run for a convergence study:

  • Run 276: MESA EOS with maxlevel increased by 1 (completed up to frame 47 and will go up to at least frame 65)

Next steps

  • Complete all runs and do basic analysis (separation vs time, energy conservation)
  • Redo unbound mass vs time plots to include only envelope gas (exclude ambient) — can wait for runs 277 and 282

CE EOS

Computing

  • Allocation on Frontera ends on Dec. 31
  • Parallel HDF5 (currently only being used for post-processing)
    • Bug has been identified and debugging ongoing (Jonathan)

EOS Runs

  • Continued analysis of Run 271:
    • New PLOT of energy terms that includes recombination energy
    • Volume integrated mass and energy released for the products of the various ionic transitions, for 3 snapshots (t=0, 23 d and 46 d)
    • Same, but divided into gas that is unbound and gas that is bound (at time t)
    • This analysis so far only on IDL (plot to screen)

Next steps

  • Do the above analysis (volume integrated mass and released energy for each species) but now for all simulation frames of Run 271, using Python
  • Continue with production runs (Stampede2 and Frontera)
  • Compute ambient unbound mass and subtract from total (as Amy has now done for jet runs)

CE (EOS)

Computing

  • Allocation on Frontera ends on Dec. 31
  • Parallel HDF5 (currently only being used for post-processing)
    • Bug has been identified and debugging ongoing (Jonathan)

EOS Runs

  • Slices comparing density of tracers for original ionization state with density of gas with a given ionization state at time t
  • Trying to improve energy conservation — Goal is to get simulation up to >100 days (c.f.~Ohlmann+16: 125 days; Prust+Chang19: 240 days)
    • Do this by testing adding refinement in different ways:
      • One extra AMR level
      • Larger region for AMR level 4
      • Larger region for max AMR level
    • Do we work to implement the new algorithm that includes gas potential energy in the explicit energy conservation (though not particle-gas potential energy) or do we carry on with what we have?
  • Energy conservation normalized to initial energy of star, not including recombination energy: Figure
    • So continuing to 100-150 days and staying <10% should be possible, particularly if we reduce softening radius 2-3 times…
    • Currently running a test where the highest AMR level refinement region is enlarged…results very soon

Next steps

  • Production runs on Frontera?
  • Compute ambient unbound mass and subtract from total (as Amy has now done for jet runs)
  • Compute total recombination energy of each species (e.g. HII, HeIII) as a function of time
  • Compute total recombination energy of each species (e.g. HII, HeIII) as a function of time for bound and unbound mass separately
    • This will tell us whether recombination energy is being released into bound gas (where it can be "useful") vs. unbound gas (where it cannot), c.f. Fig. 1 of Paper II
  • Some version of Figs. 9 and 10 of Paper IV that includes recombination energy

Fermi Project Update December 2021

Goal: find technology as a function of galactic orbital radius

  1. Find density as a function of radius

  1. Get technology as a function of density
    2a. Recreate surface plot made with Jonathan (with )

  • f is the fraction of systems that are settleable
  • is the normalized density of settleable systems within probe range
  • is the settlement civilization lifetime
  • X is the local fraction of settled systems to total systems

2b. Rerun the same parameter sweep but make

2c. Do some lineouts to get technology and X as function of density

  1. Interpolate to get density as a function of radius. (not entirely sure how to do this one)