Impactor material records the ancient lunar magnetic field in antipodal anomalies

Impact plasma amplification of the ancient lunar dynamo

Spacecraft magnetometry and paleomagnetic measurements of lunar samples provide evidence that the Moon had a magnetic field billions of years ago. Because this field was likely stronger than that predicted by scaling laws for core convection dynamos, a longstanding hypothesis is that an ancient dynamo was amplified by plasma from basin-forming impacts. However, there have been no self-consistent models that quantify whether this process can generate the required field intensities. Our impact and magnetohydrodynamic simulations show that for an initial maximum surface field of only 2 microtesla, plasmas created from basin-forming impacts can amplify a planetary dipole field at the basin antipode to ~43 microtesla. This process, coupled with impact-induced body pressure waves focusing at the antipode, could produce magnetization that can account for the crustal fields observed today.

First crustal magnetic anomaly estimates from the magnetometer observations of the Korea pathfinder lunar orbiter

First lunar crustal magnetic anomalies from the vector magnetometer onboard the Korea Pathfinder Lunar Orbiter (KPLO) called Danuri are evaluated at 100 km altitude over the areas where earlier satellite magnetic mapping missions observed strong anomalies. Although the KPLO data are still undergoing quality-control processing, the publicly available 'partially processed (PP)' data confirm five strong anomaly regions, Gerasimovich crater, Antipode of Serenitatis basin, Hayford crater, Crisium basin and Abel crater regions, where only marginal anomaly features were previously revealed at the higher altitudes. However, higher-altitude anomalies help constrain the regional effects of lunar crustal magnetic sources commonly masked by the shorter wavelengths of the shallower crustal sources. This study resolves five prominent anomaly features from six-months, PP-level KPLO magnetometer tracks by wavenumber correlation filtering. The higher-altitude anomaly features were investigated for mapping regional magnetic sources and constraining our understanding of lunar magnetism. The KPLO mission's orbital altitude decays with time to comprehensively sample the lunar magnetic anomalies for further insights on the Moon's magnetism.

Magnetometric Surveys for the Non-Invasive Surface and Subsurface Interpretation of Volcanic Structures in Planetary Exploration, a Case Study of Several Volcanoes in the Iberian Peninsula

Volcanoes are typical features of the solar system that offer a window into the interior of planets. Thus, their study can improve the understanding of the interiors and evolution of planets. On Earth, volcanoes are monitored by multiple sensors during their dormant and active phases. Presently, this is not feasible for other planets’ volcanoes. However, robotic vehicles and the recent technological demonstration of Ingenuity on Mars open up the possibility of using the powerful and non-destructive geophysical tool of magnetic surveys at different heights, for the investigation of surfaces and subsurfaces. We propose a methodology with a view to extract information from planetary volcanoes in the short and medium term, which comprises an analysis of the morphology using images, magnetic field surveys at different heights, in situ measurements of magnetic susceptibility, and simplified models for the interpretation of geological structures. This methodology is applied successfully to the study of different examples of the main volcanic zones of the Iberian Peninsula, representative of the Martian intraplate volcanism and similar to Venus domes, as a preparatory action prior to the exploration of the rocky planets’ surfaces.