Impact plasma amplification of the ancient lunar dynamo.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40408496.
- Also identified by DOI 10.1126/sciadv.adr7401 and PMC identifier 13109949.
- Licence recorded as CC BY-NC.
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Abstract
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.