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Magnetospheric ions and electrons in the distant magnetosheath at ∼50 R E and ∼180 R E : ISEE‐3 observations
Author(s) -
Scholer M.,
Hovestadt D.,
Gloeckler G.,
Klecker B.,
Ipavich F. M.,
Zwickl R. D.
Publication year - 1984
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl011i010p01098
Subject(s) - magnetosheath , physics , electron , magnetosphere , magnetopause , proton , pitch angle , atomic physics , magnetic field , ion , plasma , astrophysics , computational physics , geophysics , nuclear physics , quantum mechanics
We have analyzed energetic electron (75 ‐ 115 keV) and proton ( ∼ 30 keV) measurements at the dawn side of the distant magnetosheath at ∼ 50 R E and ∼ 180 R E . The data have been obtained during the recent ISEE‐3 Geotail Mission. At ∼ 50 R E electrons and protons occur almost simultaneously in bursts of ∼ 2 min duration. The electrons stream intensely away from the general magnetopause position along the magnetic field line. The proton angular distributions exhibit a large parallel anisotropy that is symmetric with respect to the magnetic field in the plasma frame of reference. At ∼ 180 R E almost no electrons have been so far observed above the threshold of our detector. The protons are isotropic in the plasma frame. The observations are discussed in terms of a possible model where magnetosheath flux tubes are connected to the tail magnetic field so that the magnetospheric particles can leak out. At ∼ 50R E propagation to the spacecraft is believed to be scatter‐free; after reaching ˜ 200 R E the particles have resided long enough in the magnetosheath so that they are then coupled to the magnetosheath flow via pitch angle scattering.