High - Resolution Studies of the Solar Polar

نویسنده

  • P. R. Wilson
چکیده

We present high-resolution studies of the solar polar magnetic elds near sunspot maximum in 1989 and towards sunspot minimum in 1995. We show that, in 1989, the polar latitudes were covered by several unipolar regions of both polarities. In 1995, however, after the polar eld reversal was complete, each pole exhibited only one dominant polarity region. Each unipolar region contains magnetic knots of both polarities but the number count of the knots of the dominant polarity exceeds that of the opposite polarity by a ratio of order 4:1, and it is rare to nd opposite polarity pairs, i.e. magnetic bipoles. These knots have lifetimes greater than 7 hours but less than 24 hours. We interpret the longitudinal displacement of the knots over a 7 hour period as a measure of the local rotation rate. This rotation rate is found to be generally consistent with Snodgrass' (1983) magnetic rotation law. In an attempt to obtain some insight into the operation of the solar dynamo, sketches of postulated subsurface eld conngurations corresponding to the observed surface elds at these two epochs of the solar cycle are presented.

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تاریخ انتشار 2007