Radio Frequency Signals in Jupiter's Atmosphere
During the Galileo probe's descent through Jupiter's atmosphere, under the ionosphere, the lightning and radio emission detector measured radio frequency signals at levels significantly above the probe's electromagnetic noise. The signal strengths at 3 and 15 kilohertz were relatively large at the beginning of the descent, decreased with depth to a pressure level of about 5 bars, and then increased slowly until the end of the mission. The 15-kilohertz signals show arrival direction anisotropies. Measurements of radio frequency wave forms show that the probe passed through an atmospheric region that did not support lightning within at least 100 kilometers and more likely a few thousand kilometers of the descent trajectory. The apparent opacity of the jovian atmosphere increases sharply at pressures greater than about 4 bars.
Lanzerotti
LJ
L. J. Lanzerotti, Bell Laboratories, Lucent Technologies, Murray Hill, NJ 07974, and the University of Florida, Gainesville, FL 32611, USA. K. Rinnert, Max-Planck-Institut fur Aeronomy, D-37191 Katlenburg-Lindau, Germany. G. Dehmel, F. O. Gliem, J. Bach, Universitat Braunschweig, D-38106 Braunschweig, Germany. E. P. Krider, University of Arizona, Tucson, AZ 85721, USA. M. A. Uman, University of Florida, Gainesville, FL 32611, USA.
Rinnert
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Dehmel
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Gliem
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Krider
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Uman
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Bach
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