AAS 200th meeting, Albuquerque, NM, June 2002
Session 57. Living with a Star
Display, Wednesday, June 5, 2002, 10:00am-7:00pm, SW Exhibit Hall

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[57.03] Coronal Holes and Polar Crown Filaments During Polar Reversals

P. S. McIntosh (HelioSynoptics)

Observations of coronal holes in context with polarity boundaries marked by filaments provide new insight into the reversals of polar magnetic polarity that occur a year or two after solar cycle maxima. Time series of solar synoptic charts of these data indicate the polarity reversal commences with the appearance of coronal holes, near latitude 40 degrees, that migrate poleward behind rows of filaments that form the polar crown. The polar crowns of both hemispheres move toward the poles beginning a few months after sunspot minimum and arrive at the poles about a year after sunspot maximum. After the polar polarity reversal (measured by the reversal of the average magnetic flux), the polar crown filaments fragment and disappear. The last of the polar crown filaments persist as much as a year after the polarity reversal; then, the coronal holes equatorward of the disssolving polar crown encircle, then cover, the solar poles. These become the polar caps that will persist until the next sunspot maximum. Observations of the current solar cycle reveal a surprizing possibility that the new polar coronal holes originate at sunspot maximum from remnants of polar coronal holes in the opposite solar hemisphere. A pole-to-pole migration of coronal holes is not expected with a Babcock-Leighton-Sheeley model of the solar cycle.

E-mail pmcintosh@solar.stanford.edu Telephone: 303-444-5880

The author(s) of this abstract have provided an email address for comments about the abstract: pmcintosh@solar.stanford.edu

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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.