A comparative analysis of the magnetic field signals over impact structures on the Earth, Mars and the Moon
| Autor: | Benoit Langlais, Mioara Mandea, Michael E. Purucker, Anca Isac |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Atmospheric Science
010504 meteorology & atmospheric sciences Demagnetizing field Aerospace Engineering Astronomy and Astrophysics Geophysics Mars Exploration Program 01 natural sciences Magnetic flux Physics::Geophysics Astrobiology Magnetic field Dipole Magnetic field of the Moon Impact crater Space and Planetary Science Physics::Space Physics 0103 physical sciences Hypervelocity General Earth and Planetary Sciences Astrophysics::Earth and Planetary Astrophysics 010303 astronomy & astrophysics Geology 0105 earth and related environmental sciences |
| Zdroj: | Advances in Space Research. 57:477-492 |
| ISSN: | 0273-1177 |
| DOI: | 10.1016/j.asr.2015.11.019 |
| Popis: | An improved description of magnetic fields of terrestrial bodies has been obtained from recent space missions, leading to a better characterization of the internal fields including those of crustal origin. One of the striking differences in their crustal magnetic field is the signature of large impact craters. A comparative analysis of the magnetic characteristics of these structures can shed light on the history of their respective planetary-scale magnetic dynamos. This has motivated us to identify impact craters and basins, first by their quasi-circular features from the most recent and detailed topographic maps and then from available global magnetic field maps. We have examined the magnetic field observed above 27 complex craters on the Earth, 34 impact basins on Mars and 37 impact basins on the Moon. For the first time, systematic trends in the amplitude and frequency of the magnetic patterns, inside and outside of these structures are observed for all three bodies. The demagnetization effects due to the impact shock wave and excavation processes have been evaluated applying the Equivalent Source Dipole forward modeling approach. The main characteristics of the selected impact craters are shown. The trends in their magnetic signatures are indicated, which are related to the presence or absence of a planetary-scale dynamo at the time of their formation and to impact processes. The low magnetic field intensity at center can be accepted as the prime characteristic of a hypervelocity impact and strongly associated with the mechanics of impact crater formation. In the presence of an active internal field, the process of demagnetization due to the shock impact is associated with post-impact remagnetization processes, generating a more complex magnetic signature. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect