Plasma sheet access to geosynchronous orbit

H. Korth, M. F. Thomsen, J. E. Borovsky, D. J. McComas

Research output: Contribution to journalArticlepeer-review

177 Scopus citations


One year's worth of magnetospheric plasma analyzer data from three Los Alamos geosynchronous satellites are used for a statistical study of proton and electron fluxes at geosynchronous orbit and their dependence on local time (LT) and geomagnetic activity level as measured by Kp. When displayed as a function of LT and Kp, the fluxes exhibit distinct boundaries, which are shown to be consistent with a combination of a global pattern of particle drift through the magnetosphere and loss processes mainly due to charge exchange of the ions and auroral precipitation of the electrons. A Hamiltonian energy conservation approach combined with the (U, B, K) coordinate transformation introduced by Whipple [1978] is used to calculate the theoretical-position of the separatrix between open and closed drift trajectories (Alfvén layer) as a function of particle species, energy, local time, and geomagnetic activity level. The comparison of the theoretical boundaries with the observations confirms the predictions of plasma sheet access to the geosynchronous region. The analysis also provides independent statistical support for previously derived relationships between Kp and the strength of the global convection electric field.

Original languageEnglish (US)
Article number1999JA900292
Pages (from-to)25047-25061
Number of pages15
JournalJournal of Geophysical Research: Space Physics
Issue numberA11
StatePublished - Nov 1 1999
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Atmospheric Science
  • Astronomy and Astrophysics
  • Oceanography


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