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Paper: Indices of Solar Activity in Minimum of Sunspot Cycles
Volume: 346, Large-scale Structures and their Role in Solar Activity
Page: 415
Authors: Tlatov, A.; Makarov, V.
Abstract: New indices of solar activity in minimum of sunspot cycles were obtained from the Hα synoptic charts during 1887 - 2004, CaII K observational data of solar disk during 1907 - 1995 at the Kodaikanal observatory in India and observations of the Sun at the Kislovodsk Solar Station in 1950 - 2004. Index Apz determines the area of polar zone occupied by magnetic field of one polarity and the A(t) is a sum of squares of dipole and oktopole magnetic moments. Index L(t) is a general length of magnetic neutral lines on Hα synoptic chart and the K(t) characterizes the complexity of topology pattern of general magnetic field of the Sun. It is determined by inverse number of crossing neutral lines with meridian net on Hα chart. Index R(t) determines correlation factor of polarity of the magnetic field in the latitude zones ±40°. Index of solar rotation SSPD(t) is determined by a sum of spectral density of the power of sector structures of the magnetic field. The area of CaII K bright points at the high - latitudes is the index SK(t). It was shown that the 11-year cycles of Apz(t), A(t), L(t), K(t), R(t), SSPD(t) and SK(t) have the maximum in the minimum of sunspot activity and they precede the Wolf number cycles, W(t), for 5 - 6 years.
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