Abstract
The evolution of six major active regions which appeared during the first phase of the present solar cycle (cycle 22) has been studied. It was found that the northern hemisphere regions exhibited a broad range of evolutionary behavior in which the commonly accepted ‘normal pattern’ (whereby the follower flux moves preferentially polewards ahead of the leader flux) is represented only at one end of the range. At the other end of the range, the leader flux is displaced polewards of the follower flux. In the latter cases equatorward extensions of the polar coronal hole are noted.
While it is emphasized that some of the regions in this study follow the more conventional pattern and that all regions in this study emerged during the early phase of cycle 22, the implications for theories of the solar polar field reversals are noted.
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Cannon, A.T., Marquette, W.H. The evolution and orientation of early cycle 22 active regions. Sol Phys 131, 69–78 (1991). https://doi.org/10.1007/BF00151745
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DOI: https://doi.org/10.1007/BF00151745