The magnetopause energetic electron layer, 1. Observations along the distant magnetotail
- Creators
- Baker, D. N.
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Stone, E. C.
Abstract
Observational features of the magnetopause energetic electron layer have been studied along the distant magnetotail (− 10 R_E ≳ X_(SM) ≳ −40 R_E) using California Institute of Technology instrumentation aboard Imp 8. On the basis of 101 layer crossings obtained on 60 spacecraft orbits it is concluded that the layer of electrons (E ≳ 200 keV) was present on 97% of the magnetopause crossings during 1973–1975. The inner edge of the layer is typically found to correspond to the magnetopause boundary as determined from concurrent plasma analyzer and magnetometer data. Energetic electrons within the layer are observed to be persistently streaming tailward along local magnetosheath field lines. Pitch angles of electrons along the dusk magnetopause are often restricted to values of ≲40°, whereas along the dawnside of the tail somewhat larger pitch angles are normally seen. Differential energy spectra of electrons in the layer are typically fit by power law forms with spectral indices 2 ≲ γ ≲ 4, and intensity enhancements often extend to energies of ≳1 MeV. Average directional intensities (E ≳ 200 keV) flowing through the layer are remarkably constant, ranging from ∼1 to ∼5 (cm^(−2) s^(−1)), but apparent 'hot spots' are found along the dawn flank of the magnetotail. It is suggested that these hot spots are near a source region for energetic electrons.
Additional Information
© 1978 by the American Geophysical Union. Manuscript Accepted: 3 Apr 1978. Manuscript Received: 6 Dec 1977. We thank L. A. Frank both for providing us with Imp 8 Lepedea energy-time spectograms and for many helpful discussions. We are also grateful to R. P. Lepping and N. F. Ness for providing us with the Imp8 magnetometer data through J. H. King of the National Space Science Data Center. We are grateful to R. E. Vogt who has been closely associated with this investigation, and to W. E. Althouse, G. J. Hurford, J. E. Lupton, and R. A. Mewaldt, who made significant contributions to various phases of this program. This work was supported in part by the National Aeronautics Space Administration under contract NAS5-11066 and grant NGR 05-002-160. The Editor thanks V. Domingo and another referee for their assistance in evaluating this paper.Attached Files
Published - jgra4483.pdf
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Additional details
- Eprint ID
- 43688
- Resolver ID
- CaltechAUTHORS:20140206-090120740
- NASA
- NAS5-11066
- NASA
- NGR 05-002-160
- Created
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2014-02-06Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Space Radiation Laboratory
- Other Numbering System Name
- Space Radiation Laboratory
- Other Numbering System Identifier
- 1977-01