34th Solar Physics Division Meeting, June 2003
Session 10 Transequatorial and other Coronal Structures
Oral, Tuesday, June 17, 2003, 9:00am-12:00noon, Auditorium

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[10.10] Coronal Heating and the Magnetic Flux Content of the Network

R. L. Moore (NASA/MSFC/NSSTC), D. A. Falconer (UAH/NSSTC), J. G. Porter, D. H. Hathaway (NASA/MSFC/NSSTC)

We investigate the heating of the quiet corona by measuring the increase of coronal luminosity with the amount of magnetic flux in the underlying network at solar minimum when there were no active regions on the face of the Sun. The coronal luminosity is measured from Fe IX/X-Fe XII pairs of coronal images from SOHO/EIT. The network magnetic flux content is measured from SOHO/MDI magnetograms. We find that the luminosity of the corona in our quiet regions increases roughly in proportion to the square root of the magnetic flux content of the network and roughly in proportion to the length of the perimeter of the network magnetic flux clumps. From (1) this result, (2) other observations of many fine-scale explosive events at the edges of network flux clumps, and (3) a demonstration that it is energetically feasible for the heating of the corona in quiet regions to be driven by explosions of granule-sized sheared-core magnetic bipoles embedded in the edges of network flux clumps, we infer that in quiet regions that are not influenced by active regions the corona is mainly heated by such magnetic activity in the edges of the network flux clumps. Our observational results together with our feasibility analysis allow us to predict that (1) at the edges of the network flux clumps there are many transient sheared-core bipoles of the size and lifetime of granules and having transverse field strengths > ~ 100 G, (2) ~ 30 of these bipoles are present per supergranule, and (3) most spicules are produced by explosions of these bipoles.

This work was supported by NASA’s Office of Space Science through its Solar and Heliospheric Physics Supporting Research and Technology Program and its Sun-Earth Connection Guest Investigator Program.


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Bulletin of the American Astronomical Society, 35 #3
© 2003. The American Astronomical Soceity.