Solar Physics Division Meeting 2000, June 19-22
Session 4. Magnetic Dynamo
Oral, Chair: J. T. Hoeksema, Monday, June 19, 2000, 10:30am-12:05pm, Forum

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[4.05] Orientation of Emerging Bipoles in a Filament Channel

J. Chae, P. R. Goode, T. J. Spirock, H. Wang (Big Bear Solar Observatory), S. F. Martin (Helio Research), H. S. Yun, Jung-Hoon Kim, Sangwoo Lee (SNU)

Observations have shown that quiescent prominences or filaments have a hemispheric magnetic pattern of chirality or handedness. Motivated by the question of whether the filament chirality is of sub-surface origin or not, we have studied magnetic bipoles emerging in a quiescent filament channel at latitude N45\degr. During our 5 day observing run performed in 1999 October, a huge filament erupted and another began to form in the same filament channel. Using high cadence deep line-of-sight magnetograms, we identified a total of 102 small emerging bipoles, which display the following statistical properties: 1) an average flux of 1.2\times 1019 Mx and an average separation of 7200 km; 2) an inferred global emergence frequency of 600 hr-1 all over the solar surface; and 3) a preferred orientation that a negative (trailing) pole is located at the south-east of the companion positive (leading) pole. The majority of the bipoles appear to be ephemeral regions which are systematically smaller than those previously studied with Kitt Peak full disk daily magnetograms. The preferred orientation of these bipoles differs greatly from both the filament axial field direction and the active region polarity law. We conclude that factors other than the Hale polarity law are the cause of asymmetry in the orientation of small bipoles having total magnetic fluxes below 2 \times 1019 Mx.

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