NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Theory for low-frequency modulated Langmuir wave packetsLangmuir wave packets with low frequency modulations (or beats) observed in the Jovian foreshock are argued to be direct evidence for the Langmuir wave decay L yields L-prime + S. In this decay, 'pump' Langmuir waves L, driven by an electron beam, produce backscattered product Langmuir waves L-prime and ion sound waves S. The L and L-prime waves beat at the frequency and wavevector of the S waves, thereby modulating the wave packets. Beam speeds calculated using the modulated Jovian wave packets (1) are reasonable, at 4-10 times the electron thermal speed, (2) are consistent with theoretical limits on the decay process, and (3) decrease with increasing foreshock depth, as expected theoretically. These results strongly support the theory. The modulation depth of some wave packets suggests saturation by the decay L yields L-prime + S. Applications to modulated Langmuir packets in the Venusian and terrestrial foreshocks and in a type III radio source are proposed.
Document ID
19930033006
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Cairns, Iver H.
(Iowa Univ. Iowa City, United States)
Robinson, P. A.
(Sydney Univ. Australia)
Date Acquired
August 15, 2013
Publication Date
November 20, 1992
Publication Information
Publication: Geophysical Research Letters
Volume: 19
Issue: 22
ISSN: 0094-8276
Subject Category
Lunar And Planetary Exploration
Accession Number
93A17003
Funding Number(s)
CONTRACT_GRANT: NSF ATM-90-21985
CONTRACT_GRANT: NAGW-2040
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available