We demonstrate a method of remote magnetic field measurements in the mesosphere using a laser beam with intensity modulation at the Larmor frequency of sodium, achieving an accuracy of 0.28 mG/√ Hz. This is useful as a laser guide star bright enhancement method and as a remote sensing device for magnetic fields in the mesosphere.
https://arxiv.org/abs/1802.04686
Picture: The laser shooting at the sky. A bright spot of sodium fluorescence in the mesosphere is seen in the center of the picture, along with the star HIP113889 (on the left). Above: The intensity of the fluorescent spot as a function of the angular distance from the spot’s center. The laser plume on the right side is due to Rayleigh scattering in the first 20 km of the atmosphere, while the fluorescent sodium is localized at an altitude of 90–100 km.