Remote sensing of geomagnetic fields and atomic collisions in the mesosphere.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 30266926.
- Also identified by DOI 10.1038/s41467-018-06396-7 and PMC identifier 6162266.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Magnetic-field sensing has contributed to the formulation of the plate-tectonics theory, mapping of underground structures on Earth, and the study of magnetism of other planets. Filling the gap between space-based and near-Earth observations, we demonstrate a remote measurement of the geomagnetic field at an altitude of 85-100 km. The method consists of optical pumping of atomic sodium in the mesosphere with an intensity-modulated laser beam, and ground-based observation of the resultant magneto-optical resonance near the Larmor precession frequency. Here we validate this technique and measure the Larmor precession frequency of sodium and the corresponding magnetic field with an accuracy level of 0.28 mG Hz<sup>-1/2</sup>. These observations allow the characterization of atomic-collision processes in the mesosphere. Remote detection of mesospheric magnetic fields has potential applications such as mapping magnetic structures in the lithosphere, monitoring space weather, and electric currents in the ionosphere.