EXERCISES

Reaction Networks, Nucl Physics Input, Hydro, BBN

(During-Course Assignment)

  1. Make sure everyone got the pre-test done and correct.
  2. Re-run the pre-test, reducing the temperature in the thermodynamic file
    • Find the minimum temperatures at which silicon burning, oxygen burning and carbon burning occur.
  3. Grab a new (larger, 150 species) sunet_sn150.txt from the document server.
    • Rename sunet_150.txt to sunet
    • Build a new Data directory from REACLIB
    • Create a new initial abundance file (matching the composition in the pretest)
    • Run same test problem with new network
    • Compare results to pre-test.
    • Compare timing of pre-test to new problem.

Additional possibilities:

Run a reaction network with given nuclear input for:

  1. Fixed temperature and density
    • Try various temperatures and densities
    • Try different network sizes
    • Swap out a reaction rate with a different version
    • Vary initial composition (X, Y, Z or Ye)
    • Let evolve until Nuclear Statistical Equilibrium is reached
  2. Temperature/density trajectories
  • $ T(t) = T(0)\exp{(-t/\tau)} $ or $\ T(t) = T(0)(1+\frac{t}{n\tau})^{-n} $
  • $ [1.+f_{\nu}(T(0))]\rho (t) = \rho (0) [1.+f_{\nu}(T(t))](T(t)/T(0))^3$
  • How do initial conditions affect the resulting nucleosynthesis
  • How does the trajectory form affect the results?

(Pre-Course Assignment)

Download, compile and run the Reaction Network Code

  1. Download the Reaction Network Code.
  2. Compile the code with your fortran90 compiler, following the instructions in doc/Compiling.txt in the XNet distribution.
  3. Report in the Reaction Network Code discussion thread your success with machine and compiler information.
  4. Run a first test problem, following the instructions in doc/Running.txt in the XNet distribution.
    • Your results should look like this figure.
  5. Try various temperatures and densities by changing the th_const file.