Dynamics of the transition region of the solar wind during passage to the solar-activity minimum.
Abstract
Several series of experiments on the sounding of the interplanetary plasma near the Sun were performed in 1984 - 1985 in two independent modifications of the transillumination method. The scintillations of maser sources of the water vapor line and the radial dependence of the scintillation index m(R) were studied at a wavelength of 1.35 cm. The visible angular dimensions of quasars and the radial dependence of the wave-scattering angle θ(R) were studied in the metric wave range, λ = 2.9 m. The functions m(R) and θ(R) reveal enhanced wave scattering in the zone of formation of supersonic flow, making it possible to determine the location of the transition region of the solar wind. A considerable change occurred between the series of observation in June and December 1984: the solar-activity level decreased because of the proximity to the minimum of the 11-year cycle. The sounding experiments showed that a considerable change in the position of the transition region had occurred in this time interval. The values obtained give an estimate of the maximum distance of the transition region from the Sun in the course of the 11-year cycle.
- Publication:
-
Geomagnetism and Aeronomy
- Pub Date:
- April 1989
- Bibcode:
- 1989Ge&Ae..28..621L
- Keywords:
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- Solar Wind: Solar Activity Cycles;
- Solar Wind: Interplanetary Plasma;
- Solar Wind: Variations