Further development in theory/data closure of the photoelectron-driven polar wind and day-night transition of the outflow

Sunny Wing-Yee Tam, F. Yasseen, T. Chang

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Recent in situ observations have revealed novel features in the polar wind. Measurements between 5000 and 9000 km altitude by the Akebono satellite indicate that both H+ and O+ ions can have remarkably higher outflow velocities in the sunlit region than on the nightside. Electrons also display an asymmetric behavior: the dayside difference in energy spread, greater for upward-moving than downward-moving electrons, is absent on the nightside. Here, we discuss the further development of a theory by Tam et al. that can explain most of these observed peculiar properties by properly taking into account the global, kinetic, collisional effects of the sunlit photoelectrons, on the background polar wind and the electric field. Quantitative comparisons of the calculated results with actual data will be described. In addition, transition from the daytime photoelectrondriven polar wind to the night-time polar wind will be discussed.

Original languageEnglish
Pages (from-to)948-968
Number of pages21
JournalAnnales Geophysicae
Volume16
Issue number8
DOIs
Publication statusPublished - 1998 Jan 1

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night
closures
photoelectrons
outflow
EXOS-D satellite
electron
daytime
electric field
electrons
kinetics
electric fields
ion
energy
ions

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Geology
  • Atmospheric Science
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

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abstract = "Recent in situ observations have revealed novel features in the polar wind. Measurements between 5000 and 9000 km altitude by the Akebono satellite indicate that both H+ and O+ ions can have remarkably higher outflow velocities in the sunlit region than on the nightside. Electrons also display an asymmetric behavior: the dayside difference in energy spread, greater for upward-moving than downward-moving electrons, is absent on the nightside. Here, we discuss the further development of a theory by Tam et al. that can explain most of these observed peculiar properties by properly taking into account the global, kinetic, collisional effects of the sunlit photoelectrons, on the background polar wind and the electric field. Quantitative comparisons of the calculated results with actual data will be described. In addition, transition from the daytime photoelectrondriven polar wind to the night-time polar wind will be discussed.",
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Further development in theory/data closure of the photoelectron-driven polar wind and day-night transition of the outflow. / Tam, Sunny Wing-Yee; Yasseen, F.; Chang, T.

In: Annales Geophysicae, Vol. 16, No. 8, 01.01.1998, p. 948-968.

Research output: Contribution to journalArticle

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