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Paper: The Progress of Solar Cycle 24 at High Latitudes
Volume: 428, SOHO-23: Understanding a Peculiar Solar Minimum
Page: 147
Authors: Altrock, R. C.
Abstract: The “extended” solar cycle 24 began in 1999 near 70° latitude, similarly to cycle 23 in 1989 and cycle 22 in 1979. The extended cycle is manifested by persistent Fe XIV coronal emission appearing near 70° latitude and slowly migrating towards the equator, merging with the latitudes of sunspots and active regions (the “butterfly diagram”) after several years. Cycle 24 began its migration at a rate 40% slower than the previous two solar cycles, thus indicating the possibility of a peculiar cycle. However, the onset of the “Rush to the Poles” of polar crown prominences and their associated coronal emission, which has been a precursor to solar maximum in recent cycles (cf. Altrock 2003), has just been identified in the northern hemisphere. Peculiarly, this “rush” is leisurely, at only 50% of the rate in the previous two cycles. The properties of the current “Rush to the Poles” yields an estimate of 2013 or 2014 for solar maximum.
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