High-latitude coronal holes and polar faculae in the 21st–23rd solar activity cycles

Abstract

The latitude-time evolution of large high-latitude coronal holes (CHs) and polar faculae (PF) during the period 1975–2010 has been studied. Their spatial distribution relative to each other has been considered. CHs and PF are shown to pass two significantly different phases in their evolution during an 11-year cycle. At phase I, i.e., during the period of an increase and maximum in the 11-year cycle, large CHs and PF exhibit a sequential motion from heliolatitudes of 40°–50° to the polar region and form a series of discrete chains with a periodicity of 1.25 ± 0.3 years in the 21st cycle. The magnetic field in CH chains corresponds to the trailing polarity of spot groups of this cycle. The anomaly of the 23rd cycle at high latitudes manifested itself in a break of the aforesaid periodicity in the N-hemisphere by the formation of a discontinuity between the second and third chains with a duration of three years. This shifted the beginning of the next 24th cycle by three years.