Motions and interactions among large-scale solar structures on H-alpha synoptic charts

Interactions among large-scale cells of polarity and between coronal holes and polarity features are studied with H-alpha synoptic charts that now span the period October 1964 through February 2004 (Solar Cycles 20-23). These data give a detailed record of the poleward migration of polar crown filaments, revealing the coexistence of primary and secondary polar crowns in each hemisphere. The polar crown gap (PCG) in each hemisphere is a distinctive feature from the first year of the solar cyle until the PCCs close at sunspot maximum four years later. The northern PCG closures occurred exactly at sunspot maximum in 3 of the 4 cycles. The large-scale polarity patterns at latitude 30 change abruptly at sunspot minimum, coinciding within a month of the minimum. A single polarity cell is identified as the origin of the "rush" to the poles of the northern polar crown filaments.