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Voyager 2 observations of energetic particle variations in the Ganymede wake region - A possible acceleration mechanismVoyager 2's passage through the downstream corotation region of Ganymede found disturbances in the field and particle environment. Large fluctuations in the intensities and energy spectra of ions in the 0.1-to 4.0-MeV interval were also observed with the low energy charged particle experiment. All ion species were evidently affected, up through medium (C, N, O) nuclei. Electrons intensities, while disturbed, did not behave similarly to the ions. These effects are probably associated with the wake produced by the absorption of Jovian magnetospheric corotating plasma by Ganymede. A two-dimensional theoretical model for perturbed field in the wake region is proposed and it is shown by direct numerical simulation of exact particle trajectories that such perturbations are capable of modulating the charged particle energies to about the observed amount for the observed magnetic and plasma parameters. Analysis shows that the energization process is dependent on the pitch angles of the energetic ions and the process itself is nonadiabatic (the Larmor radius is approximately the size of the disturbance region).
Document ID
19830056363
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Tariq, G.F.
(Kansas Univ. Lawrence, KS, United States)
Armstrong, T. P.
(Kansas Univ. Lawrence, KS, United States)
Collison, T. H.
(Kansas, University Lawrence, KS, United States)
Date Acquired
August 11, 2013
Publication Date
July 1, 1983
Publication Information
Publication: Journal of Geophysical Research
Volume: 88
ISSN: 0148-0227
Subject Category
Lunar And Planetary Exploration
Accession Number
83A37581
Funding Number(s)
CONTRACT_GRANT: NAGW-154
PROJECT: PROJECT VOYAGER
TASK: NASA TASK I
OTHER: N00024-78-C-5384
Distribution Limits
Public
Copyright
Other

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