Cross Sections

AURORA includes electron-impact cross sections for the three main neutral species in the upper atmosphere: N₂, O₂, and atomic O. For each species, elastic and inelastic (excitation of rotational, vibrational, electronic states and ionization) cross-sections are included.

These data are loaded internally when an AuroraModel is constructed.

Data sources

The cross-section data are primarily based on:

• Itikawa, Y. (2006). Cross sections for electron collisions with nitrogen molecules. J. Phys. Chem. Ref. Data, 35(1), 31–53.
• Itikawa, Y. (2009). Cross sections for electron collisions with oxygen molecules. J. Phys. Chem. Ref. Data, 38(1), 1–20.
• Itikawa, Y. & Ichimura, A. (1990). Cross sections for collisions of electrons and photons with atomic oxygen. J. Phys. Chem. Ref. Data, 19(3), 637–651.

Emission cross sections

In addition to the collision cross sections used by the transport solver, AURORA includes cross sections for specific auroral optical emissions. These are used by make_volume_excitation_file to compute volume excitation rates. The following emission lines are currently implemented: