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Low‐charge‐state heavy ions upstream of Earth's bow shock and sunward flux of ionospheric O +1 , N +1 , and O +2 ions: Geotail observations
Author(s) -
Christon S. P.,
Desai M. I.,
Eastman T. E.,
Gloeckler G.,
Kokubun S.,
Lui A. T. Y.,
McEntire R. W.,
Roelof E. C.,
Williams D. J.
Publication year - 2000
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 - 10.1029/2000gl000039
Subject(s) - physics , ionosphere , flux (metallurgy) , ion , magnetosphere , solar wind , noon , geophysics , incoherent scatter , cosmic ray , earth's magnetic field , astrophysics , atomic physics , atmospheric sciences , plasma , nuclear physics , magnetic field , materials science , quantum mechanics , metallurgy
Energetic ∼10–210 keV/e low‐charge‐state heavy ions (LCSHI) were measured sunward of Earth's bow shock (to X ∼ 30 R E ) during numerous intervals lasting from minutes to hours using Geotail/STICS in 1995–1998. LCSHI fluxes are strong and continuous in a few tens of intervals, during which a strong component of ionospheric origin O +1 , N +1 , and O +2 streams sunward on nearly radial IMF. Most often though only ‘trace’ levels are present. LCSHI flux is typically, but not exclusively, observed during diffuse upstream ion events. LCSHI are accompanied by sunward energetic electron bursts in three of the four cases shown and twice by enhanced IMF fluctuations. As O +1 streams sunward in the spacecraft frame during the strongest case, H + , He +2 , He +1 , and O +6 fluxes have weak anisotropies and the H + energy spectrum is kappa‐like. The strongest LCSHI fluxes tend to occur duskward of local noon during disturbed geomagnetic conditions. On average, LCSHI flux is more uniformly distributed across the dayside.