Probing the viability of Auroral optics inversion with a rendering model

Electron transport models such as the Global airgLOW model (GLOW) use specified electron distributions to produce volume emission rates of several wavelengths resulting from physical and chemical processes in the upper atmosphere. Such models can be used to invert filtered optical imagery back into electron spectra. For a Maxwellian electron population, the energy flux of the electrons and the brightness of the 427.8 nm emission are linearly related, except for very low energies. The average energy of a Maxwellian electron population can be inverted via the 844.6 nm to 557.7 nm ratio or via 630.0 nm to 557.7 nm. However, Maxwellian aurora is not the only type of aurora, so this study also includes Maxwellian-based inversions of Alfvenic and monoenergetic aurora. Additionally, the errors from oblique measurements (i.e. when a pixel’s line of sight is not parallel to local magnetic zenith) will be quantified for different arc geometries and incident spectra.

A rendering model has been constructed to (1) take a 2D grid electron energy flux and average energy, (2) populate a simulated sky with volume emission rates via GLOW, (3) render multiwavelength images, and (4) perform the energetics inversion. The output is then compared to the input to highlight geometric errors and errors associated with assumptions of the electron spectra during inversion. This poster will present this process for Maxwellian, Alfvenic, and monoenergetic cases of different arc shapes and positions.