Jovian electron populations in the magnetosphere of Mercury

A mechanism to explain the existence of two distinctly different kinds of energetic electron bursts within the Hermean magnetosphere is presented. The spectrally‐soft, very intense increases of energetic electrons observed in situ by Mariner 10 are ascribed to "substorm‐like" dissipation events due to magnetic reconnection in Mercury's magneto tail. The other type of electron bursts observed in Mercury's magnetosphere, characterized by lower peak intensities and much harder energy spectra, are attributed to Jovian electrons which first enter and are subsequently confined in the Hermean system. This Jovian electron model at Mercury is closely analogous to a similar model of such Jovian electron effects within the terrestrial magnetosphere. Such a model eliminates the need for the Hermean magnetosphere to produce highly relativistic electron bursts by internal generation mechanisms.