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Session 8 - Corona III.
Oral session, Saturday, June 28
Ballroom A, Chair: Barry LaBonte

[8.03] Time Variability of Polar Plumes as observed with SoHO/EIT and SoHO/MDI

C. E. DeForest (Stanford University), J. B. Gurman (NASA / Goddard Space Flight Center), J. D. Moses (Naval Research Lab)

Polar plumes are magnetically open high density structures that are observed in the polar coronal holes. They arise from unipolar magnetic footpoints in between chromospheric network cells, and expand as they rise through the corona to altitudes of at least 15-20 solar radii. On timescales of hours, plumes are remarkably stable, quiescent structures; however, we find that plumes vary significantly in XUV intensity on time scales of a few minutes and length scales of about an arc minute, based on high cadence observations in the EIT 171A and 195A passbands. The observed variations propagate outward with speeds of about 300 km/sec. We demonstrate this effect in several plumes observed during different EIT high cadence pole observations; compare observed variations in the photospheric field, as measured simultaneously by MDI, to the intensity variations in the plumes; and suggest whether the outward motions represent physical structures or wave motion.

If you would like more information about this abstract, please follow the link to mdiwww.nascom.nasa.gov/~zowie/papers/plume-variability. This link was provided by the author. When you follow it, you will leave the the Web space for this meeting; to return, you should use the Back button on your browser.

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

Program listing for Saturday