INTRODUCTION

• Line emissions are a principal diagnostic of neutral species,
  • Intensities provide information about neutral density,
  • As well as plasma background.
  • Spectral information velocity distribution [Stotler, 1996].
• Simulating emissions via neutral transport code
  • Validates (or invalidates) plasma background used relative to data,
  • Provides aid in interpreting diagnostics,
    • E.g., Relating 2-D emission distributions to chord-integrated data.
  • Yields another benchmark of code physics,
    • Particularly atomic physics data.
• Once code has been matched to data,
  • Can apply knowledge of neutral distribution to interpret other phenomena,
  • Or to suggest hardware modifications, e.g., pumps or baffles.
• Use DEGAS 2 [Stotler, 1994] Monte Carlo neutral transport code to
  simulate line emission in an Alcator C-Mod detached plasma,
  • See adjacent poster by Karney for other code details,
  • Plasma model described in more detail in [Stotler, 1997].
  • These are examples; production modeling
    awaits better methods of generating plasma data,
    • Coupling DEGAS 2 to fluid plasma code,
    • Transport analysis code based on measured profiles.