Mystery of the Mercury’s anomalous magnetic field solved.
Feb. 6, 2019
Like the Earth, planet Mercury has its own magnetic field generated by the dynamo action in the core. Comparison of Mercury’s magnetic field with the geomagnetic field using the magnetic dipole reveals that Mercury’s dipole is offset northward from the planet’s center, while the Earth’s magnetic dipole is at the geocenter (Fig. 1). This was discovered by the MESSENGER spacecraft in 2011. However, it was still unresolved why Mercury has such an anomalous magnetic field unlike the geomagnetic field.
The research group consisting of Drs. Futoshi Takahashi from Faculty of Science, Kyushu University, Hisayoshi Shimizu from Earthquake Research Institute, University of Tokyo, and Hideo Tsunakawa from School of Science, Tokyo Institute of Technology, clearly addressed the big question using numerical dynamo modeling mimicking the thermochemical structure of Mercury’s interior. The Mercury’s offset magnetic field is spontaneously generated and stably maintained by core convection, which is governed by the self-regulating effect of the dynamo-generated magnetic field (Fig. 2).
This study was supported by JSPS KAKENHI (JP15K05270, JP15H05834, JP18K03808). The paper, ”Mercury’s anomalous magnetic field caused by a symmetry-breaking self-regulating dynamo” has been published online in Nature Communications 10, Article: 208 (2019): https://rdcu.be/bgKbe .