NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
an unusual rotationally modulated attenuation band in the jovian hectometric radio emission spectrumA well-defined attenuation band modulated by the rotation of Jupiter has been found in the spectrum of Jovian hectometric radiation using data from the Galileo plasma wave instrument. The center frequency of this band usually occurs in the frequency range from about 1 to 3 MHz and the bandwidth is about 10 to 20 percent. The center frequency varies systematically with the rotation of Jupiter and has two peaks per rotation, the first at a system III longitude of about 50 deg, and the second at about 185 deg. It is now believed that the attenuation occurs as the ray path from a high-latitude cyclotron maser source passes approximately parallel to the magnetic field near the northern or southern edges of the Io L-shell. The peak at 50 deg system 3 longitude is attributed to radiation from a southern hemisphere source and the peak at 185 deg is from a northern hemisphere source. The attenuation is thought to be caused by coherent scattering or shallow angle reflection from field-aligned density irregularities near the Io L-shell. The narrow bandwidth indicates that the density irregularities are confined to a very narrow range of L values (Delta L = 0.2 to 0.4) near the Io L-shell.
Document ID
19990008247
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Gurnett, D. A.
(Iowa Univ. Iowa City, IA United States)
Kurth, W. S.
(Iowa Univ. Iowa City, IA United States)
Menietti, J. D.
(Iowa Univ. Iowa City, IA United States)
Persoon, A. M.
(Iowa Univ. Iowa City, IA United States)
Date Acquired
August 19, 2013
Publication Date
June 1, 1998
Publication Information
Publication: Geophysical Research Letters
Volume: 25
Issue: 11
ISSN: 0094-8534
Subject Category
Lunar and Planetary Exploration
Report/Patent Number
Paper-98GL01400
Funding Number(s)
CONTRACT_GRANT: NAS9-58779
Distribution Limits
Public
Copyright
Other