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Ion burst event in the Earth's dayside magnetosheath
Author(s) -
Paschalidis N. P.,
Krimigis S. M.,
Sarris E. T.,
Sibeck D. G.,
McEntire R. W.,
Christon S. P.,
Zanetti L. J.
Publication year - 1991
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 - 10.1029/91gl00140
Subject(s) - magnetosheath , magnetopause , physics , solar wind , magnetosphere , geophysics , earth's magnetic field , magnetic field , ion , computational physics , astrophysics , quantum mechanics
The MEPA instrument on the AMPTE/CCE Spacecraft provided ion angular distributions as rapidly as every 6 sec for H, He, and O at energies of 10 keV to 2 MeV in the dayside magnetosheath whenever the solar wind pressure compressed the magnetopause within 8.75 R E , the CCE apogee. In this report we discuss a burst of energetic particles in the subsolar magnetosheath and its association with rapid changes in the local magnetic field direction in such a way that the magnetic field connected the spacecraft to the magnetopause during the enhancement. We find that magnetosheath angular distributions outside the burst peaked at 90° pitch angles, whereas during the burst they exhibited field aligned streaming either parallel or antiparallel to the magnetic field combined with a clear earthward gradient. The clear earthward gradients at E ≥ 10 KeV, the streaming, and the slope change in the burst‐time magnetosheath spectrum at ∼10 KeV suggest magnetospheric source for the burst‐time ≥10 KeV ions and heated solar wind for E < 10 KeV.