ET Workshop Fall 2011 RAD

Possibilities

• Leakage scheme
  • very ad-hoc
  • only mimicks loss due to radiation
• Diffusion equation
  • accurate only when mean free path is really short
  • almost always implicit to avoid strong CFL limit
  • cheap, usually inaccurate
• Flux limited diffusion
  • Diffusion + "trick" at lower optical depths
  • also simple, and has been used for supernovae simulations
  • unclear if working in GR
  • limits radiation speed: ad-hoc
  • also not very accurate
• Two-Moment-Scheme / Truncated moment scheme
  • start with Boltzmann equation
  • decompose into moments
  • truncate series
  • close using some prescription (approximate the rest of the series)
• Monte-Carlo