Letter | Published:

Spectral broadening measurements of the ionospheres of Jupiter and Saturn

Abstract

When Pioneers 10 and 11 flew by Jupiter, their 2.3-GHz monochromatic radio signals underwent substantial spectral broadening as they propagated through the planet's ionosphere1,2. Although spectral broadening has been observed during radio occultation by the solar corona3,4, the Pioneer measurements of Jupiter represent the first time it has been observed during radio occultation by a planetary atmosphere. The Pioneer data are also unique in that r.f. spectral broadening, a scattering phenomenon normally associated with strong intensity scintillations (σ2χ 1 where σ2χ is the variance of the log-amplitude scintillations), occurred when the intensity scintillations were weak. This unusual opportunity makes it possible to compare the theory for spectral broadening with the more widely used weak intensity scintillation theory5,6. We report here that good agreement is found, and present the inferred characteristics of the electron density irregularities for the ionospheres of both Jupiter and Saturn. The Saturn results are based on measurements made during the 1979 Pioneer 11 encounter of Saturn.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1

    Kliore, A. et al. Science 188, 474 (1975).

  2. 2

    Fjeldbo, G., Kliore, A., Seidel, B., Sweetnam, D. & Cain, D. Astr. Astrophys. 39, 91 (1975).

  3. 3

    Goldstein, R. M. Science 166, 598 (1969).

  4. 4

    Woo, R. & Armstrong, J. W. J. geophys. Res. 84, 7288 (1979).

  5. 5

    Tartarskii, V. I. The Effects of the Turbulent Atmosphere on Wave Propagation (National Technical Information Service, Springfield, 1971).

  6. 6

    Ishimaru, A. Wave Propagation and Scattering in Random Media Vol. 2 (Academic, New York, 1978).

  7. 7

    Woo, R. & Yang, F. C. J. Geophys, Res. 83, 5245 (1978).

  8. 8

    Woo, R., Yang, F. C. & Ishimaru, A. Astrophys. J. 210, 593 (1976).

  9. 9

    Woo, R., Yang, F. C. & Ishimaru, A. Astrophys. 218, 557 (1977).

  10. 10

    Kliore, A. et al. Science 207, 446 (1980).

  11. 11

    Fejer, B. G. & Kelley, M. C. Rev. Geophys. Space Phys. 18, 401 (1980).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.