Small magnetic bipoles emerging in a filament channel

Observations have shown that quiescent prominences or filaments have a hemi spheric magnetic pattern of chirality. Motivated by the question of whether the filament chirality is of subsurface origin or not, we have studied sma ll magnetic bipoles that emerged in a quiescent filament channel at latitud e N45 degrees. During our 5 day observing run, performed in 1999 October, a huge filament erupted and reformed shortly in the same filament channel. U sing high-cadence, long-integration line-of-sight magnetograms taken at Big Bear Solar Observatory, we identified a total of 102 bipoles that showed a n average total flux of 2.8 x 10(19) Mx, an average separation of 7400 km a t the time of full development, and an emergence rate of 430 hr(-1) per the entire solar surface area. These properties indicate that most of the bipo les are ephemeral regions. The most important finding in the present study is that the magnetic axes of the bipoles emerging in the filament channel a re systematically oriented; a negative (trailing) pole is observed to be lo cated preferentially to the south-east of its companion positive (leading) pole. This preferred orientation does not match either the Hale law of acti ve region orientation or a theory that attributes the axial field of a fila ment to emerging bipoles. We propose two possible subsurface field configur ations of bipoles consistent with the observed preferential orientation and discuss physical implications of our results for understanding filament ma gnetic fields.