Recurrent high-speed streams in the solar wind during the decay phase of solar cycle No. 21: observations with a wide-angle ion energy spectrometer on Prognoz-9

Solar wind measurements were made on Prognoz 9 from July 1983 to February 1984 during the decay phase of solar cycle No. 21. The measurements were made by means of the D-137A wide-angle ion energy spectrometer. During this time period, high-speed streams were observed in the solar wind which were stable for intervals of 5-6 solar rotations. In several of the streams, the speed was as high as 700-800 km/sec. They have compared the Prognoz 9 data with data obtained by analogous measurements in the preceding solar cycle. This comparison leads them to the conclusion that the presence of recurrent high-speed streams is a regular feature during the decay phases of the 11-yr cycles of solar activity, and is one of the manifestations of these cycles