Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Site Tools

  • AAAS
  • Subscribe
  • Feedback

Site Search

Search Advanced

Science 15 December 1989:
Vol. 246. no. 4936, pp. 1489 - 1494
DOI: 10.1126/science.246.4936.1489
Prev | Table of Contents | Next

Articles

Energetic Charged Particles in the Magnetosphere of Neptune

E. C. Stone 1, A. C. Cummings 1, M. D. Loooper 1, R. S. Selesnick 1, N. Lal 2, F. B. McDonald 2, J. H. Trainor 2, and D. L. Chenette 3

1 California Institute of Technology, Pasadena, CA 91125
2 NASA Goddard Space Flight Center, Greenbelt, MD 20771
3 Lockheed Palo Alto Research Laboratory, Palo Alto, CA 94304

The Voyager 2 cosmic ray system (CRS) measured significant fluxes of energetic [ge1 megaelectron volt (MeV)] trapped electrons and protons in the magnetosphere of Neptune. The intensities are maximum near a magnetic L shell of 7, decreasing closer to the planet because of absorption by satellites and rings. In the region of the inner satellites of Neptune, the radiation belts have a complicated structure, which provides some constraints on the magnetic field geometry of the inner magnetosphere. Electron phase-space densities have a positive radial gradient, indicating that they diffuse inward from a source in the outer magnetosphere. Electron spectra from 1 to 5 MeV are generally well represented by power laws with indices near 6, which harden in the region of peak flux to power law indices of 4 to 5. Protons have significantly lower fluxes than electrons throughout the magnetosphere, with large anisotropies due to radial intensity gradients. The radiation belts resemble those of Uranus to the extent allowed by the different locations of the satellites, which limit the flux at each planet.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Magnetic Fields at Neptune.
N. F. Ness, M. H. Acuna, L. F. Burlaga, J. E. P. Connerney, R. P. Lepping, and F. M. Neubauer (1989)
Science 246, 1473-1478
   Abstract »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)