Differential Measurement and Model Calculations of Cosmic-Ray Latitudinal Gradient with Respect to the Heliospheric Current Sheet
Abstract
Simultaneous magnetic field and charged particle measurements from the Voyager spacecraft with heliographic latitude separations of >10° are used to investigate the distribution of ∼1-GeV galactic cosmic ray protons with respect to the heliospheric current sheet in the outer solar system. By comparing the ratio of cosmic ray flux at Voyager 1 to that at Voyager 2 during periods of relatively quiet interplanetary conditions when the spacecraft are either both north or both south of the heliospheric current sheet, we derive an average latitude component of the gradient of the cosmic ray flux on opposite sides of the current sheet under restricted interplanetary conditions of −0.22±0.03%/deg, equivalent to a decrease of ∼1%/AU away from the current sheet at ∼12 AU. Our results for these limited periods are in qualitative agreement with propagation models incorporating particle drifts.
Additional Information
© 1986 by the American Geophysical Union. Received July 31, 1985; revised October 1, 1985; accepted October 2, 1985. We are grateful to R. E. Vogt for his contributions to the Cosmic Ray Subsystem on the Voyager spacecraft and to N. F. Ness, the principal investigator for the GSFC MAG experiment, for the magnetic field data from the Voyager spacecraft used in this study. We appreciate the contributions of the other Voyager Cosmic Ray subsystem team members-scientists and engineers at the California Institute of Technology, the Goddard Space Flight Center, the University of Arizona, and the University of New Hampshire. Work at Caltech was supported in part by the National Aeronautics and Space Administration under contract JPL 49-556-63120-0-2600 and grant NGR 05-002-160. Work at Arizona was supported in part by the National Aeronautics and Space Administration under grant NSG 7101, by the National Science Foundation grant ATM-220-18, and by the International Study Program of the National Science Foundation. The idea for this study originated in discussions at a meeting of the Cosmic Ray Modulation Workshop. The Editor thanks R. Decker and G. Newkirk for their assistance in evaluating this paper.Attached Files
Published - 1985-24.pdf
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Additional details
- Eprint ID
- 45312
- Resolver ID
- CaltechAUTHORS:20140429-131447506
- JPL
- 49-556-63120-0-2600
- NASA
- NGR 05-002-160
- NASA
- NSG 7101
- NSF
- ATM-220-18
- NSF International Study Program
- Created
-
2014-04-29Created from EPrint's datestamp field
- Updated
-
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
- 1985-24