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Cometary H 2 + and solar wind He 2+ dynamics across the Halley cometopause
Author(s) -
Fuselier S. A.,
Shelley E. G.,
Balsiger H.,
Geiss J.,
Goldstein B. E.,
Goldstein R.,
Ip W. H.
Publication year - 1988
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/gl015i006p00549
Subject(s) - physics , comet , solar wind , halley's comet , dissociation (chemistry) , ion , ionization , spectrometer , astrophysics , atomic physics , astronomy , plasma , nuclear physics , chemistry , optics , quantum mechanics
Two Mass/Charge (M/Q) ≈ 2 distributions were observed by the Giotto Ion Mass Spectrometer/High Energy Range Spectrometer (IMS/HERS) during the encounter with comet Halley. The first, present throughout the encounter, is identified as solar wind He 2+ . The second, detectable only within ∼6 × 10 5 km of the nucleus, is identified as H 2 + (produced primarily by dissociation and ionization of cometary H 2 O). When these two distributions are separated, distinct differences in their dynamics are apparent, particularly in the density and velocity profiles near the “cometopause”.