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Energetic atomic and molecular ions of ionospheric origin observed in distant magnetotail flow‐reversal events
Author(s) -
Christon S. P.,
Gloeckler G.,
Williams D. J.,
Mukai T.,
McEntire R. W.,
Jacquey C.,
Angelopoulos V.,
Lui A. T. Y.,
Kokubun S.,
Fairfield D. H.,
Hirahara M.,
Yamamoto T.
Publication year - 1994
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 - 10.1029/94gl02095
Subject(s) - ionosphere , physics , ion , solar wind , plasma sheet , geophysics , earth's magnetic field , plasma , astrophysics , atmospheric sciences , atomic physics , magnetosphere , magnetic field , quantum mechanics
Energetic atomic (O +1 and N +1 ) and molecular (O 2 +1 , NO +1 , and N 2 +1 ) ions of ionospheric origin were observed in Earth's magnetotail at X ∼ −146 R E during two plasma sheet sunward/tailward flow‐reversal events measured by instruments on the GEOTAIL spacecraft. These events were associated with concurrent ground‐measured geomagnetic disturbance intensification at auroral‐ and mid‐latitudes ( Kp = 7 − ). Energetic ions in the sunward‐component and tailward flows were from both the solar wind and ionosphere. Plasma and energetic ions participated in the flows. During tailward flow, ionospheric origin ion abundance ratios at ∼200–900 km/s in the rest frame were N +1 /O +1 = ∼25–30% and (O 2 +1 , NO +1 , and N 2 +1 ) /O +1 = ∼1–2%. We argue that tailward flow most likely initiated ∼80–100 R E tailward of Earth and molecular ions were in the plasma sheet prior to geomagnetic intensification onset.