Fixing Crashes on Transition to RSG

Diagnostic:

  • code crash during central helium burning, usually during an early stage for solar metallicity, may be later for Pop III stars

  • outermost few zone are alreay convective; this is barely visible on mass coordianate plot, you need to plot as a function of radius

    p 132 1
    plot 1
    

    often you will see up to tow small convection zone

  • the code tries to reduce timestep by a lot - you will see many backups

  • the time step may already be very small

Possible solutions:

  • if the time step is not yet small, try to allow more backups; it may require more than 10 backups, but should definitvely not be more than 20

    p 52 20
    
  • if the time step is already small, the code may need to recover.

    • The first thing to try is to change correction factor during iteration, fmin (p 375). Set it to a smaller number, e.g.,

      p 375 .1
      
    • Next, try to increase linear viscosity, q1fac (p 13) to a high number, e.g.,

      p 13 1000.
      

      Warning

      Do not forget to set it back to the original value, usually 0.1 during normal evolution, when the code has recovered to a large time step!

      p 13 .1