Miniature Dungey-like cycle at Mars

With its non-uniform distribution of crustal magnetic fields, Mars exhibits complex and highly variable auroral patterns related to both planetary rotation and solar wind conditions. Using in situ electron, ion, and magnetic field data from the Mars Atmospheric and Volatile EvolutioN (MAVEN) mission, we show that auroral processes associated with these small-scale crustal magnetic fields can be understood in terms of a miniature cycle of magnetic flux and plasma circulations that resemble a miniature version of what occurs at the Earth. However, at Earth, this Dungey cycle, named after its discoverer, operates in the presence of a global intrinsic dipole field with a strength approximately 100 times stronger and spatial scales roughly 20 times larger. From a universal perspective, the current finding adds an entry to the zoo of auroral concepts that enriches our understanding of the diversity of (exo)planetary plasma and our understanding of how planets interact with their space environments.