Abstract
Current theoretical models of Saturn's ionosphere are similar to those of Jupiter's because of the gross similarity of their upper atmospheres. In the case of Jupiter, the theoretical models can be fitted reasonably well to ionospheric electron density profiles1,2 obtained from the Pioneer and Voyager radio occultation experiments3–5. In contrast, the theoretical models of Saturn's ionosphere are inconsistent with both the ionospheric electron density profiles6,7 obtained from the Pioneer and Voyager occultation observations8–10 and the large diurnal variation of maximum ionospheric electron density deduced from studies of Saturn lightning discharges11,12. We propose a radically different model of Saturn's ionosphere in which water plays a major role as a minor constituent present by downward diffusion from an external source. Our model Saturn ionosphere is a classical ‘F2’ type layer resulting from the photodissociative production of H+ from H2 and rapid chemical loss by a series of charge exchange reactions with water. A planet-wide influx of ∼4 × 107 molecules cm−2 s−1 of water from the rings is consistent with the observed ionospheric electron densities. An enhanced influx of water occurs at latitudes (−38°, +44°) connected magnetically to the inner edge of Saturn's B ring12 where an electromagnetic erosion process13 takes place. Present-day influx at these latitudes may be as large as ∼2 × 109 molecules cm−2 s−1.
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References
Atreya, S. K. & Donahue, T. M. in Jupiter (ed. Gehrels, T.) 304–318 (University of Arizona Press, Tucson, 1976).
Strobel, D. F. & Atreya, S. K. in Physics of the Jovian Magnetosphere (ed. Dessler, A. J.) 51–66 (Cambridge University Press, Cambridge, Massachusetts, 1983.
Fjeldbo, G., Kliore, A., Seidel, B., Sweetnam, D. & Cain, D. Astron. Astrophys. 39, 91–96 (1975).
Eshleman, V. R. et al. Science 204, 976–978 (1979).
Eshleman, V. R. et al. Science 206, 959–962 (1979).
Atreya, S. K. & Waite, J. H. Nature 292, 682–683 (1981).
Atreya, S. K., Waite, J. H., Donahue, T. M., Nagy, A. F. & McConnell, J. C. in Saturn (ed. Gehrels, T.) 239–279 (University of Arizona Press, Tucson, 1984).
Kliore, A. J. et al. J. geophys. Res. 85, 5857–5870 (1980).
Tyler, G. L. et al. Science 212, 201–206 (1981).
Tyler, G. L. et al. Science 215, 553–558 (1982).
Kaiser, M. L., Connerney, J. E. P. & Desch, M. D. Nature 303, 50–53 (1983).
Kaiser, M. L., Desch, M. D. & Connerney, J. E. P. J. geophys. Res. 89, 2371–2376 (1984).
Northrop, T. G. & Hill, J. R. J. geophys. Res. 88, 6102–6108 (1983).
Waite, J. H., Atreya, S. K. & Nagy, A. F. Geophys. Res. Lett. 6, 723–726 (1979).
Atreya, S. K. & Donahue, T. M. Icarus 24, 358–362 (1975).
Shimizu, M. Proc. 13th Lunar planet. Symp. 709 (1980).
Chen, R. S. Moon Planets 28, 37–41 (1983).
Giguere, P. T. & Huebner, W. F. Astrophys. J. 223, 638–654 (1978).
Huebner, W. F. & Carpenter, C. W. Los Alamos Scientific Laboratory Report LA-8085-MS (1979).
Bauer, S. J. Physics of Planetary Ionospheres (Springer, New York, 1973).
Rishbeth, H. Rev. Geophys. 6, 33–71, 1968.
Morfill, G. E., Fechtig, H., Grun, E. & Goertz, C. K. Icarus 55, 439–447 (1983).
Carlson, R. W. Nature 283, 461 (1980).
Winkelstein, P. et al. Icarus 54, 309–318 (1983).
Samuelson, R. E. et al. J. geophys. Res. 88, 8709–8715 (1983).
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Connerney, J., Waite, J. New model of Saturn's ionosphere with an influx of water from the rings. Nature 312, 136–138 (1984). https://doi.org/10.1038/312136a0
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DOI: https://doi.org/10.1038/312136a0
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