University of California at Berkeley, CA 94720, USA
Enhanced fluxes of relativistic electrons are observed intermittently in the terrestrial radiation belt during recovery phase of magnetic storm, and in the interplanetary medium following solar impulsive events. The processes in planetary magnetospheres are initiated with a deformation of terrestrial magnetic field due to an external loading, while the mechanisms responsible for electron energization to relativistic energies are controversial. The enhancements in the interplanetary medium follow deformation of the coronal flaring field, mostly after coronal shock or mass ejection. It is suggested that both the terrestrial and the solar energization mechanism rely on excitation of whistler waves which propagate along the inhomogeneous magnetic field, due to low energy electrons which are injected by substorm reconnection or coronal shock, respectively. The delayed heliospheric energization occurs due to an additional distant reconfiguration, as observed by microwave bursts. The flare serves mainly as a time reference for the electromagnetic emissions, while the propagating CME subsequently opens an access for the relativistic electrons to the interplanetary medium. In the terrestrial environment an effective energization takes place only when an injection of low-energy substorm electrons occurs in the recovery phase of magnetic storm. The time scales are accordingly few hours and tens of minutes, respectively. Similar process may operate in gamma ray bursts or in other astrophysical configurations, on a faster time scale.