RADIO SCIENCE WITH VOYAGER-1 AT JUPITER - PRELIMINARY PROFILES OF THE ATMOSPHERE AND IONOSPHERE

A preliminary profile of the atmosphere of Jupiter in the South Equatorial Belt shows (i) the tropopause occurring at a pressure level of 100 millibars and temperature of about 113K, (ii) a higher warm inversion layer at about the 35-millibar level, and (iii) a lower-altitude constant lapse rate matching the adiabatic value of about 2 K per kilometer, with the temperatutre reaching 150 K at the 600-millibar level. Preliminarv afternoon and predawn ionospheric profiles at 120 south latitude and near the equator, respectively, have topside plasma scale heights of 590 kilometers changing to 960 kilometers above an altitude of 3500 kilometers for the dayside, and about 960 kilometers at all measured heights above the peak for the nightside. The higher value of scale height corresponds to a plasma temperature of 1100 K under the assuinption of a plasma of protons and electrons in ambipolar diffusive equilibrium. The peak electron concentration in the upper ionosphere is approximately 2×10 5 per cubic centimneterfor the davside and about a factor of 10 less for the nightside. These peaks occur at altitudes of 1600 and 2300 kilometers, respectively. Continuing analyses are expected to extend and refine these results, and to be used to investigate other regions and phenomena. Copyright © 1979 AAAS.