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Abstract :
[en] Mars' lack of a global magnetic field led to low expectations for aurora. Mars Express's SPICAM instrument nonetheless discovered an unusual form of aurora in 2005. The UV emissions were confined near Mars' strong crustal field region, showing that even weak magnetic fields can be responsible for aurora.
MAVEN arrived at Mars in 2014 carrying the Imaging UltraViolet Spectrograph (IUVS). Thanks to its high mid-UV sensitivity and observing cadence, IUVS increased detections of discrete aurora twenty-fold. IUVS also discovered two new types: diffuse aurora, a planet-engulfing phenomenon, caused by solar energetic particles directly impacting the entire unshielded planet, and proton aurora, caused by solar wind protons charge-exchanging into the atmosphere causing Lyman alpha emission across the dayside. IUVS studies the aurora at in the mid-UV and far-UV in both limb scans and nadir imaging.
The Emirates Mars Mission (EMM) arrived in 2021 carrying the Emirates Mission UltraViolet Spectrometer (EMUS). EMUS quickly added new auroral phenomena thanks to its high far-UV sensitivity. Discrete aurora emissions were seen in a substantial fraction of nightside observations, and appear to take on new forms not seen by IUVS (sinuous, "non-crustal field", among others). Furthermore, EMUS detected a spatially-variable form of proton aurora called patchy proton aurora. Together these suggest more diverse physical processes are at work. EMUS studies the aurora through nadir imaging at far- and extreme-UV wavelengths.
This presentation seeks to give a broader context of these observations made with different instruments at different wavelength ranges in different observing modes
- what phenomena IUVS and EMUS observe, depending on their distinct instrumental capabilities
- whether they’re actually seeing the same phenomena or different ones,
how can one type of observation can complement the other,
- where one’s capabilities are unique, and
- what are the best directions for collaboration;
- how in situ measurements of particles and fields can contribute to the next stage of understanding particle precipitation
A more coherent observational perspective, as outlined above, may grant a framework for developing a deeper physical understanding of Mars unexpectedly diverse auroral processes.
