Method for remotely measuring the spin-damping time of mesospheric sodium

By using the return flux enhancement factor due to repumping, the spin-damping time of mesospheric sodium can be estimated. Because the absolute return photon number does not need to be measured, this method is independent of sodium abundance. An example of how to find the spin-damping time using this method is given. As a result, it is shown that this method is sensitive and has the potential to improve the precision of the spin-damping time estimations of mesospheric sodium. Finally, the impact of the geomagnetic field on this method is analyzed.