Title: The Unique Seasonal Influence of the Interplanetary Magnetic Field on Martian Proton Aurora

We evaluate for the first time the large-scale influence of the upstream interplanetary magnetic field (IMF) magnitude and orientation on Martian proton aurora. We specifically look at IMF magnitude and orientations to consider how these factors influence the brightness and likelihood of occurrence for proton aurora activity. Ten years of proton auroral observations from the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft (Jakosky et al., 2015) are utilized in this study. We identify a moderate correlation between proton aurora activity and IMF magnitude that varies seasonally, with highest correlations around Mars southern summer solstice when proton aurora activity reaches an annual high. We also identify preferentially increased proton aurora emission enhancements at IMF cone and clock angles consistent with the shape of the Parker spiral at Mars’s heliocentric distance. An increased proton aurora occurrence rate is observed for near- and quasi-radial IMF orientations, however, this correlation is only observed during seasons other than around southern summer solstice, when the hydrogen corona and bow shock are annually decreased. Lastly, proton aurora are observed to exhibit preferentially higher occurrence rates under strong ±Bz orientations, consistent with the findings of recent studies (e.g., Bowers et al., 2023) which identified conditions of increased likelihood for dayside magnetic reconnection at Mars (i.e., between the IMF and Martian crustal fields) for similar altitudes and geographic locations. Thus, our results suggest that dayside magnetic reconnection may influence Martian proton aurora occurrence. These findings enhance our understanding of the interconnected relationship between proton aurora and the Mars magnetic field environment, as well as the upstream IMF’s role as an important driver of Martian proton aurora activity.