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Exploration of Solar Wind Acceleration Region Using Interplanetary Scintillation of Water Vapor Maser Source and QuasarsSingle-station observations of interplanetary scintillation UPS) at three microwave frequencies 2, 8, and 22GHz, were carried out between 1989 and 1998 using a large (34-micro farad) radio telescope at the Kashima Space Research Center of the Communications Research Laboratory. The aim of these observations was to explore the near-sun solar wind, which is the key region for the study of the solar wind acceleration mechanism. Strong quasars, 3C279 and 3C273B, were used for the Kashima IPS observations at 2 and 8GHz, and a water-vapor maser source, IRC20431, was used for the IPS observations at 22GHz. Solar wind speeds derived from Kashima IPS data suggest that the solar wind acceleration takes place at radial distances between 10 and 30 solar radii (Rs) from the sun. The properties of the turbulence spectrum (e.g. anisotropy, spectral index, inner scale) inferred from the Kashima data were found to change systematically in the solar wind acceleration region. While the solar wind in the maximum phase appears to be dominated by the slow wind, fast and rarefied winds associated with the coronal holes were found to develop significantly at high latitudes as the solar activity declined. Nevertheless, the Kashima data suggests that the location of the acceleration region is stable throughout the solar cycle.
Document ID
20020006321
Acquisition Source
Marshall Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Tokumaru, Munetoshi
(Communications Research Lab. Japan)
Yamauchi, Yohei
(NASA Marshall Space Flight Center Huntsville, AL United States)
Kondo, Tetsuro
(Communications Research Lab. Japan)
Date Acquired
August 20, 2013
Publication Date
March 1, 2001
Publication Information
Publication: Review of the Communications Research Laboratory
Volume: 47
Issue: 1
ISSN: 0914-9279
Subject Category
Solar Physics
Distribution Limits
Public
Copyright
Other

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