- 1Swedish Institute of Space Physics (IRF), Solar System Physics and Space Technology (SSPT), Kiruna, Sweden (thomas.maynadie@irf.se)
- 2Physical Research Laboratory, 380009 Ahmedabad, India.
- 3University of Bern, Space Research & Planetary Sciences Division, 3012 Bern, Switzerland.
- 4Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, 252-5210 Kanagawa, Japan
Despite lacking a global magnetic field, the Moon features localized magnetized regions called lunar magnetic anomalies [1]. Their interaction with the solar wind results in significant proton reflection and deflection [2], creating unique structures often referred to as lunar mini-magnetospheres [3, 4]. Previous studies have shown that the largest magnetic anomaly, the South Pole-Aitken (SPA) cluster, induces global-scale perturbations in the near-surface lunar plasma environment on both the dayside [5, 6] and nightside [7]. However, its influence on the plasma environment in south polar regions remains unknown.
In this study, we produce new composite images of backscattered energetic neutral hydrogen derived from Sub-KeV Atom Reflecting Analyzer (SARA) [8] data. These images reveal that plasma perturbations generated by the SPA cluster can extend to lunar south-polar regions, depending on local time and upstream solar wind conditions. These perturbations affect solar wind proton precipitation patterns, either decreasing or enhancing impinging proton fluxes depending on whether the south pole lies downstream or outside of the SPA anomaly. Based on these observations, we develop an empirical model of solar wind compression by the SPA cluster to evaluate its impact on ion instrument measurements at the south pole.
Understanding the complex interactions between the plasma, dust, and electromagnetic environments is an important asset to ensure safe and sustainable human presence on the Moon. We will discuss the role of the SPA cluster in these interactions, which will establish preliminary measurement requirements for in-situ plasma instruments in polar regions.
References:
[1] Coleman et al. (1972), Physics of the Earth and Planetary Interiors, https://doi.org/10.1016/0031-9201(72)90050-7.
[2] Lue et al. (2011), Geophysical Research Letters, https://doi.org/10.1029/2010GL046215.
[3] Lin et al. (1998), Science, https://doi.org/10.1126/science.281.5382.1480.
[4] Wieser et al. (2010), Geophysical Research Letters, https://doi.org/10.1029/2009GL041721.
[5] Fatemi et al. (2014), Journal of Geophysical Research: Space Physics, https://doi.org/10.1002/2014JA019900.
[6] Maynadié et al. (2024), Europlanet Science Congress 2024, Berlin, https://doi.org/10.5194/epsc2024-79.
[7] Dhanya et al. (2018), Geophysical Research Letters, https://doi.org/10.1029/2018GL079330.
[8] Barabash et al. (2009), Current Science, http://www.jstor.org/stable/24105464.
How to cite: Maynadié, T., Futaana, Y., Barabash, S., Bhardwaj, A., Wurz, P., and Asamura, K.: Effects of the South Pole-Aitken Magnetic Anomaly Cluster on the Plasma Environment at the Lunar South Pole, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4290, https://doi.org/10.5194/egusphere-egu25-4290, 2025.
