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Interaction between neutral hydrogen and solar wind: Spacecraft measurements of H + at the Earth's orbit
Author(s) -
Egidi A.,
Francia P.,
Villante U.
Publication year - 1984
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/gl011i008p00709
Subject(s) - solar wind , physics , ion , polar wind , hydrogen , spacecraft , satellite , flux (metallurgy) , range (aeronautics) , computational physics , orbit (dynamics) , magnetopause , atmospheric sciences , atomic physics , environmental science , magnetic field , astronomy , chemistry , materials science , organic chemistry , quantum mechanics , engineering , composite material , aerospace engineering
Measurements taken by the solar wind experiment aboard the ISEE 2 satellite show evidence for H + ions, originating from neutral hydrogen moving with a speed much lower than that of the solar wind. Positive ion fluxes are measured as a function of energy and flow direction and accumulated over a time of few hours, in which the solar wind and magnetic field parameters remain approximately constant. A model given by Vasyliunas and Siscoe (1976) is used to predict the expected location of these ions in velocity space. A consistent correlation is found between predictions and measurements in three periods of time; order of magnitude estimates of the ion flux range between 10 4 and 10 5 cm −2 s −1 . In the region surrounding the Earth, the neutral hydrogen consists primarily of interstellar and geocoronal gas. The present preliminary results presented do not allow to evaluate the relative contributions of the two populations to the observed fluxes.