Other
Scientific paper
May 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000spd....31.0123h&link_type=abstract
American Astronomical Society, SPD Meeting #31, #01.23; Bulletin of the American Astronomical Society, Vol. 32, p.805
Other
Scientific paper
Ephemeral regions are bipolar regions of magnetic flux, emerging all over the solar surface, with a typical lifetime of 4.4 hrs. Ephemeral regions and active regions are distinguished by a rather arbitrary size limit of 2.5 square degrees. In this paper, a 3.5 day sequence of full disk magnetograms is studied, taken by the MDI-instrument on SOHO. An algorithm is developed to recognize ephemeral regions on these magnetograms. The chosen data set was taken with a high frequency of, on average, one magnetogram per minute, during a total time span of 3.5 days. In each image, all coherent magnetic concentrations are selected. Subsequently, two opposite-polarity concentrations of comparable total flux content, situated closer to one another than 10 Mm, are interpreted as bipoles. These bipoles can be associated with newly emerged ephemeral regions, but may also be the result of chance encounters of previously existing opposite-polarity concentrations. Pairs of images are compared, interspaced by 95 - 100 minutes, in order to determine which bipoles do not overlap magnetic concentrations in the previous image, within a radius of 19 Mm. We find a total number of (1-2)104 ephemeral regions, on 1/4 of the total solar surface. The total amount of flux emerging in ephemeral regions is estimated to be of order 1016}-10{17 Mx/sec. This flux, emerging in ephemeral regions, provides a significant fraction of the total flux on the solar surface. We discuss the implications for the total flux balance on the entire sun. This work was supported by the SOI/MDI project at Stanford and LMSAL (grant NAG5-3077).
No associations
LandOfFree
Recognition of Ephemeral Regions on a sequence of full-disk MDI magnetograms does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Recognition of Ephemeral Regions on a sequence of full-disk MDI magnetograms, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Recognition of Ephemeral Regions on a sequence of full-disk MDI magnetograms will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1348046