Location of the source for the energetic electron layer at the polar magnetopause and its relation to magnetic reconnection

Journal Article · Mon Jun 01 04:00:00 EDT 1981 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA086iA06p04579· OSTI ID:6214761

Formisano, V; Domingo, V; Wenzel, K

The existence of a layer of energetic (> or approx. =20 keV) electrons along the magnetopause, extending from the polar cusp region to the distant magnetotail, has been established by measurements on various spacecraft. We have performed a statistical study of electron flux and spectral measurements above 0.5 MeV observed in different regions of the magnetopause accessible to HEOS 2, with the aim of identifying the source for this magnetopause electron layer. The measurements along the polar magnetotail (i. e., adjacent to the plasma mantle), along the mid-latitude dayside magnetopause (i.e.,adjacent to the dayside plasma boundary layer), and on both sides of the magnetosheath/polar cusp interface (i.e., in the exterior polar cusp and in the entry layer) have been separately analyzed and are statistically compared. We conclude that escape of electrons from the magnetosphere can be excluded as a significant source for the tail magnetopause layer on the basis of the observed intensities, of the spectra, and of the frequency of appearance of electrons outside those magnetopause regions which lie adjacent to the outer trapping zone. The electron intensities in the exterior polar cusp region are found to be correlated with the north/south component of the interplanetary magnetic field (IMF). High intensity levels are observed when the IMF is directed southward (B/sub z/<0), and low levels when the IMF points northward (B/sub z/>0). The electron flux in the exterior cusp region at times of southward IMF and at the near-earth polar magnetotail at times of northward IMF is well correlated with the number of field lines carried by the solar wind towards the magnetosphere (expressed by the product of solar wind speed and interplanetary field magnitude). We interpret this as strong evidence that acceleration processes associated with magnetic reconnection occur at the magnetopause at those times.

• Research Organization: Space Science Department, European Space Research nd Technology Centre, Noordwijk, The Netherlands
• OSTI ID: 6214761
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 86:A6; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640203* -- Atmospheric Physics-- Magnetospheric Phenomena-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
EARTH ATMOSPHERE
ELECTRON DENSITY
ELECTRONS
ELEMENTARY PARTICLES
ENERGY RANGE
ENERGY SPECTRA
FERMIONS
INTERPLANETARY MAGNETIC FIELDS
KEV RANGE
LEPTONS
MAGNETIC FIELD CONFIGURATIONS
MAGNETIC FIELDS
MAGNETOPAUSE
MAGNETOSPHERE
MAGNETOTAIL
SPECTRA