Bright Rims Adjacent to a Quiescent H$\alpha$ Filament

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Session 123 -- Solar Magnetic Field and Solar Variabilty
Oral presentation, Thursday, 12, 1995, 2:00pm - 3:30pm

[123.04] Bright Rims Adjacent to a Quiescent H$\alpha$ Filament

V.Gaizauskas (NRCC/HIA), E.De Luca, L.Golub (SAO), H.P.Jones (NASA/GSFC)

Recent models of filament-formation invoke reconnection between small-scale magnetic elements adjacent to the polarity inversion line separating large areas of unipolar magnetic fields. In an attempt to confirm this process, we examine joint observations of a quiescent filament straddling the SW limb of the Sun during the total solar eclipse of 1991 July 11. We test a hypothesis that a signature of the reconnection process might be carried by the prominent bright rims beside or enclosed between curved feet, or 'barbs', which connect the body of the H$\alpha$ filament to structures near the base of the atmosphere.

We spatially register digitized H$\alpha$ (ORSO) images of the filament with coronal (NIXT) images and with photospheric magnetograms (NSO/KP) to a precision of +/- 2". Our findings relate to five rims, elongated bright patches in H$\alpha$ with a maximum length of 20". We find a better spatial association of the rims with bipolar magnetic elements (4/5) than with small patches of weakly enhanced soft X-rays (2/4). We point out that projection effects at these extreme limb positions could alter these associations.

We conclude from these limited 'snapshot' observations that we are not yet able to decide whether or not bright rims on quiescent prominences are locations of magnetic reconnection on a small scale. Because reconnection is highly dynamic, compelling evidence for or against this process will have to await prolonged observations at multiple wavelengths in X-rays of a single filament at high spatial and temporal resolution, such as those envisaged for the Transition Region and Coronal Explorer (TRACE).

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