2021/03/10 by Y. Bai, Yang Bai, S. Q. Lu +2
Physics and Astronomy · #Astrophysics #Astrophysics and Cosmic Phenomena #Computational physics #Condensed matter physics #Dipole model of the Earth's magnetic field #Earth's magnetic field #Electron magnetic dipole moment #Interplanetary magnetic field #L-shell #Magnetic dipole #Magnetic energy #Magnetic field #Magnetic flux #Magnetic moment #Magnetic monopole #Magnetization #Mercury's magnetic field #Physics #Quantum electrodynamics #Quantum mechanics #Radio Astronomy Observations and Technology #Solar and Space Plasma Dynamics #Solar wind #astro-ph.EP #hep-ph
paper · pdf · doi:10.1103/physrevlett.127.101801
published as Phys. Rev. Lett. 127, 101801 (2021) · 14 pages, 5 figures
arxiv created 2021/03/10 · openalex publication_date 2021/08/31 · arxiv updated 2021/09/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Magnetic monopoles have long been predicted in theory and could exist as a stable object in our Universe. As they move around in galaxies, magnetic monopoles could be captured by astrophysical objects like stars and planets. Here, we provide a novel method to search for magnetic monopoles by detecting the monopole moment of Earth's magnetic field. Using over six years of public geomagnetic field data obtained by the Swarm satellites, we apply Gauss's law to measure the total magnetic flux, which is proportional to the total magnetic charge inside Earth. To account for the secular variation of satellite altitudes, we define an altitude-rescaled magnetic flux to reduce the dominant magnetic dipole contribution. The measured magnetic flux is consistent with the existing magnetic field model that does not contain a monopole moment term. We therefore set an upper limit on the magnetic field strength at Earth's surface from magnetic monopoles to be |Bm|<0.13 nT at 95% confidence level, which is less than 2×10-6 of Earth's magnetic field strength. This constrains the abundance of magnetically charged objects, including magnetic black holes with large magnetic charges.