Io encounters past and present: A heavy ion comparison
Abstract
The heavy ion counter (HIC) on the Galileo spacecraft consists of two low-energy telescopes that were proof-test models of the telescopes used for the cosmic ray subsystem (CRS) on Voyager. The telescopes on HIC were improved to better withstand the intense radiation environment of the Jovian system and to measure higher-energy particles with greater sensitivity. The similarity of these two instruments makes it natural to compare the data in an effort to glean insight on the behavior of heavy ion fluxes at higher energies and how the inner Jovian magnetosphere has changed in the last 18 years. Inside L = 6, the oxygen spectrum suggests a spectral break at ∼ 7500 MeV/Gauss, corresponding to ions with gyroradii of ∼ 1.5 R_(Io) at L = 6. A comparison of the phase space densities show remarkable agreement between the two time periods outside of the Io orbit, with differential spectra consistent with γ ∼ −8 above ∼ 6 MeV/nucleon. Near Io Galileo observed a large density gradient not apparent in the Voyager data that may be due to local time asymmetries or a decrease in the radial diffusion rate.
Additional Information
© 2000 American Geophysical Union. Received January 21, 1999; revised December 1, 1999; accepted December 1, 1999. Janet G. Luhmann thanks both referees for their assistance in evaluating this paper.Attached Files
Published - jgra14859.pdf
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Additional details
- Eprint ID
- 48965
- Resolver ID
- CaltechAUTHORS:20140827-090127162
- Created
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2014-08-27Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Space Radiation Laboratory
- Other Numbering System Name
- Space Radiation Laboratory
- Other Numbering System Identifier
- 2000-40