Simulating the Reiner Gamma Swirl: The Long‐term Effect of Solar Wind Standoff
Résumé
The Reiner Gamma swirl is a prime location to investigate the lunar albedo patterns and their co‐location with magnetic anomalies. The precise relationship between impinging plasma and the swirl, and in particular, how these interactions vary over the course of a lunar day, remains an open issue. Here we use a fully kinetic particle‐in‐cell code, coupled with a magnetic field model based on orbital‐altitude observations, and simulate the interaction with the Reiner Gamma anomaly for all plasma regimes the region is exposed to along a typical orbit, including different solar wind incidence angles and the Moon's crossing through the terrestrial magnetosphere. Consistent with the hypothesis that swirls form as a result of plasma interactions with near‐surface magnetic fields, we show that the energy flux profile produces a pattern similar to Reiner Gamma's alternating bright and darkly colored bands, but only when integrating over the full lunar orbit. We additionally show that including He2+ as a self‐consistent plasma species improves the match.
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