Space Science Reviews

, Volume 72, Issue 1–2, pp 117–120 | Cite as

Pioneer and Voyager observations of large-scale spatial and temporal variations in the solar wind

  • P. R. Gazis
  • A. Barnes
  • J. D. Mihalov
Session 2: Large-Scale Heliospheric Structure

Abstract

The Pioneer 10, Pioneer 11, and Voyager 2 spacecraft were launched in 1972, 1974, and 1977, respectively. While these three spacecraft are all at compartively low heliographic latitudes compared with Ulysses, their observation span almost two solar cycles, a range of heliocentric distances from 1 to 57 AU, and provide a unique insight into the long-term variability of the global structure of the solar wind. We examine the spatial and temporal variation of average solar wind parameters and fluxes. Our obsevations suggest that the global structure of the outer heliosphere during the declining phase of the solar cycle at heliographic latitudes up to 17.5°N was charaterized by two competing phenomena: 1) a large-scale increase of solar wind density, temperature, mass flux, dynamic pressure, kinetic energy flux, and thermal enery flux with heliographic latitude, similar to the large-scale latitudinal gradient of velocity seen in IPS observations, 2) a small-scale decrease in velocity and temperature, and increase in density near the heliospheric current sheet, which is associated with a band of low speed, low temperature, and high density solar wind similar to that observed in the inner heliosphere.

Keywords

Solar Wind Solar Cycle Current Sheet Global Structure Latitudinal Gradient 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Bame, S. J., et al.: 1993,Geophys. Res. Lett. 20, 2323Google Scholar
  2. Gazis, P. R.: 1993,J. Geophys. Res. 98, 9391Google Scholar
  3. Gazis, P. R.: 1994,J. Geophys. Res. in pressGoogle Scholar
  4. Gazis, P. R., et al.: 1989,Geophys. Res. Lett. 16, 223Google Scholar
  5. Hoeksema, J. T., et al.: 1983,J. Geophys. Res. 88, 9910Google Scholar
  6. Mitchell, D. G., et al: 1981,J. Geophys. Res. 86, 165Google Scholar
  7. Miyake, W. et al: 1981,J. Geophys. Res. 94, 15,359Google Scholar
  8. Rhodes, E. J., and Smith, E. J.: 1981,J. Geophys. Res. 86 8877Google Scholar
  9. Schwenn, R.: 1994,28th Symposium of the ESLAB,Google Scholar
  10. Sime, D. G., and Rickett, B. J.: 1978,J. Geophys. Res. 83 5757Google Scholar
  11. Zhao, Xue-Pu and Hundhausen, A. J.: 1981,J. Geophys. Res. 86, 5423Google Scholar

Copyright information

© Kluwer Academic Publishers 1995

Authors and Affiliations

  • P. R. Gazis
    • 1
    • 2
  • A. Barnes
    • 1
  • J. D. Mihalov
    • 1
  1. 1.NASA Ames Research CenterMoffett FieldUSA
  2. 2.San Jose State University FoundationUSA

Personalised recommendations