Search for auroral signatures in the Martian ionosphere using MAVEN/ROSE electron density profiles

At Mars, three types of aurorae have been discovered so far. The first kind of aurora is discrete aurora (Soret et al., 2021, and references therein), in which smaller patches of aurora are created mainly in the nighttime sector of the planet by particles accelerated to energies <1 keV by magnetic field reconfiguration; the altitude of emission is at about 135 km. The second kind is diffuse aurora (Schneider et al., 2018, and references therein), in which the aurora spans much of the Martian nightside and is caused by solar energetic particles accelerated to energies of about 100 keV; the peak emission altitudes are between 60 and 70 km. The third kind is proton aurora, which occurs preferentially on the Martian dayside (Hughes et al., 2019, and references therein) and is caused by penetrating protons from the solar wind; the emission enhancement appears between 110 and 150 km altitude.

 

We use electron density profiles collected by the MAVEN Radio Occultation Science Experiment (ROSE) (Withers et al., 2020) to understand what ionospheric structures are associated with these three different types of auroral emissions, and how the energy deposited by the precipitating particles generating these three types of aurorae affects the electron density in the ionosphere and at what altitudes. We do this by comparing ROSE data to MAVEN/IUVS detections of discrete, diffuse, and proton aurora close spatially and temporally to ROSE observations; and ROSE data to particle data displaying conditions that potentially could have triggered the aurorae.   

 

References

Soret, L., Gérard, J.-C., Schneider, N., Jain, S., Milby, Z., Ritter, B., et al. (2021). Discrete aurora on Mars: Spectral properties, vertical profiles, and electron energies. Journal of Geophysical Research: Space Physics, 126, e2021JA029495. https://doi.org/10.1029/2021JA029495

Schneider, N. M., Jain, S. K., Deighan, J., Nasr, C. R., Brain, D. A., Larson, D., et al. (2018). Global aurora on Mars during the September 2017 space weather event. Geophysical Research Letters, 45, 7391–7398.https://doi.org/10.1029/2018GL077772

Hughes, A., Chaffin, M., Mierkiewicz, E., Deighan, J., Jain, S., Schneider, N., et al. (2019). Proton aurora on Mars: A dayside phenomenon pervasive in southern summer. Journal of Geophysical Research: Space Physics, 124, 10,533–10,548. https://doi.org/10.1029/2019JA027140

Withers, P., Felici, M., Mendillo, M. et al. The MAVEN Radio Occultation Science Experiment (ROSE). Space Sci Rev 216, 61 (2020). https://doi.org/10.1007/s11214-020-00687-6