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Plasma wave electric fields in the solar wind - Initial results from Helios 1Plasma-wave measurements by Helios 1 show that the electric-field intensities in the solar wind are usually very low, much lower than those for comparable measurements near earth, where particles moving upstream from the bow shock often cause large disturbances in the solar wind. The most commonly occurring plasma wave detected by Helios is a sporadic emission at frequencies from about 1 to 10 kHz, between the electron and ion plasma frequencies. These waves are thought to be ion acoustic waves Doppler-shifted upward in frequency from below the ion plasma frequency. The maximum electric-field intensity of these waves is a few hundred microvolts per meter. At higher frequencies, from about 20 to 100 kHz, electron plasma oscillations are detected at frequencies near the local electron plasma frequency. These electron plasma oscillations are more intense, with field strengths sometimes as large as a few millivolts per meter, but occur very infrequently. Both the ion acoustic waves and the electron plasma oscillations show a tendency to occur at higher frequencies closer to the sun but no pronounced variation in intensity with radial distance from the sun. In four cases, electron plasma oscillations have been found in association with type III radio bursts.
Document ID
19770040367
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Gurnett, D. A.
(Max-Planck-Institut fuer extraterrestrische Physik, Garching, West Germany; Iowa, University Iowa City, Iowa, United States)
Anderson, R. R.
(Iowa, University Iowa City, Iowa, United States)
Date Acquired
August 8, 2013
Publication Date
February 1, 1977
Publication Information
Publication: Journal of Geophysical Research
Volume: 82
Subject Category
Solar Physics
Accession Number
77A23219
Funding Number(s)
CONTRACT_GRANT: NGL-16-001-043
CONTRACT_GRANT: NAS5-11279
Distribution Limits
Public
Copyright
Other

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