Synchrotron radiation of electrons trapped in earth's magnetosphere

Relatively large fluxes of trapped electrons with energy above several tens of MeV in the inner radiation belt, established according to low altitude satellite measurements, invoked the question of their production of synchrotron radiation in geomagnetic field. Based on experimental data on electrons, rough estimate of the spectral density of synchrotron radiation at the Equator is obtained in the region of maximum emissivity. Relatively low value of the radiation flux implies that only precise measurements at 1 GHz allowing to measure the directivity of emissions may be relevant.