Energetic and relativistic electrons near the polar magnetopause
Abstract
More than 2 years of Heos 2 observations in the high-latitude outer magnetosphere and magnetosheath have confirmed the presence of a layer of energetic and relativistic electrons near the polar tail magnetopause. This layer, appearing as ‘electron spike’ on almost every magnetopause crossing, contains electrons over a wide range of energies up to relativistic energies of >2 MeV. Their differential energy spectrum, if fitted by a power law, has an average spectral index between 3 and 4.5. The spikes are typically 1-2 RE wide extending more into the magnetosheath than into the magnetosphere. The electron intensity in the magnetopause layer decreases with distance along the tail, away from the polar cusp, and increases with increasing Kp values. It tends to be higher when the magnetosheath field is parallel or antiparallel to the tail magnetic field. In many cases the magnetopause spikes are accompanied by spikes in the magnetosheath which often follow closely the fluctuations of the magnetosheath field direction and/or intensity. A map of the average electron distribution in the polar magnetosphere and magnetosheath is presented.
- Publication:
-
Journal of Geophysical Research
- Pub Date:
- June 1977
- DOI:
- 10.1029/JA082i016p02327
- Bibcode:
- 1977JGR....82.2327D
- Keywords:
-
- High Energy Electrons;
- Magnetopause;
- Magnetospheric Electron Density;
- Polar Regions;
- Relativistic Particles;
- Electron Distribution;
- Geomagnetic Tail;
- Geomagnetism;
- Heos Satellites;
- Magnetosheath;
- Polar Orbits;
- Spectral Emission;
- Particles and Fields-Magnetosphere: Magnetopause;
- Particles and Fields-Magnetosphere: Magnetosheath