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Detection of energetic hydrogen molecules in Jupiter's magnetosphere by Voyager 2: Evidence for an ionospheric plasma source
Author(s) -
Hamilton D. C.,
Gloeckler G.,
Krimigis S. M.,
Bostrom C. O.,
Armstrong T. P.,
Axford W. I.,
Fan C. Y.,
Lanzerotti L. J.,
Hunten D. M.
Publication year - 1980
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/gl007i010p00813
Subject(s) - magnetosphere , jovian , physics , jupiter (rocket family) , magnetosphere of jupiter , atmosphere of jupiter , ionosphere , astronomy , planet , astrobiology , gas giant , astrophysics , plasma , exoplanet , saturn , nuclear physics , magnetopause , space shuttle
We report the discovery of energetic ( ∼ 1 MeV/nuc) H 3 and H 2 molecules in Jupiter’s magnetosphere. The data, obtained with the LECP instrument on Voyager 2, showed these molecules to be present throughout the magnetosphere and as far as 180 R J from the planet, in the “magnetospheric wind” region. Although the relative abundances of H 3 and H 2 do not show a monotonic trend with distance from Jupiter, the intervals of highest abundance were found in the outer magnetosphere. As an example, in the radial range 51‐56 R J of the dayside magnetosphere, the abundances of H 3 and H 2 (0.60‐0.95 MeV/nuc) were about 20% and 13‐25% that of He, respectively, and the He abundance was about 1‐2% that of H. Since H 3 + is expected to be an important constituent of Jupiter’s ionopshere, our data provide strong evidence that, in addition to Io, the ionsphere may be an important local plasma source for the Jovian energetic particles. To our knowledge, the measurements reported here represent the first detection in nature of molecules at energies as high as 1 MeV/nucleon.