ET Workshop Fall 2011 RAD

Possibilities

• 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