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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 (IPS) at three microwave frequencies; 2 GHz, 8 GHz and 22 GHz have been carried out between 1989 and 1998 using a large (34 m farad) radio telescope at the Kashima Space Research Center of the Communications Research Laboratory. The aim of these observations is 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 Kashima IPS observations at 2 GHz and 8 GHz, and a water vapor maser source, IRC20431 was used for the IPS observations at 22 GHz. Solar wind velocities derived from Kashima IPS data suggest that the solar wind acceleration takes place at radial distances between 10 and 30 solar radii (R(sub s)) from the sun. Properties of the turbulence spectrum (e.g. anisotropy, spectral index, inner scale) inferred from Kashima data are 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 coronal holes are found to develop significantly at high latitudes as the solar activity declines. Nevertheless, Kashima data suggests that the location of the acceleration region is stable throughout the solar cycle.
Document ID
20020011026
Acquisition Source
Marshall Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Tokumaru, Munetoshi
(Nagoya Univ. Space Physics Japan)
Yamauchi, Yohei
(NASA Marshall Space Flight Center Huntsville, AL United States)
Kondo, Tetsuro
(Communications Research Lab. Tokyo, Japan)
Date Acquired
August 20, 2013
Publication Date
March 1, 2001
Publication Information
Publication: Journal of the Communications Research Laboratory. Special Issue: Large Aperture Radio Telescopes at Kashima Space Research Center
Volume: 48
Issue: 1
ISSN: 0914-9260
Subject Category
Solar Physics
Distribution Limits
Public
Copyright
Other

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