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Session 1 - Chromosphere, Corona, Flares.
Display session, Friday, June 27
Ballroom B, Chair: Charles Kankelborg
Several recent theoretical models explain coronal activity in terms of magnetic reconnection at ``separator'' field lines. These are field lines lying at the boundary between domains of coronal flux with distinct photospheric origin. Transient brightenings of X-ray loops (Shimizu et al. 1992) may be the manifestations of such localized events (Longcope 1996). Their relative simplicity, compared to large events such as flares, makes them ideal objects for exploring reconnection models. Toward this end, a campaign of coordinated observations of loop brightenings in a small active region was undertaken on June 6, 1996. High time cadence observations were made of the transition region and low corona in EUV (SUMER and CDS) and of the high corona in soft X-rays (Yohkoh), while high cadence, high resolution vector magnetograms were obtained with the Imaging Vector Magnetograph at the University of Hawaii. This series of magnetograms is used to calculate the magnetic topology of the coronal field, and to locate the separator field lines. The high time cadence of the magnetograms allows the estimation of reconnection rates: the rate at which flux must be exchanged between domains. The "minimum current corona" model (Longcope 1996) is then used to provide quantitative predictions of energy released on each separator due to this reconnection. The observational results of the campaign are described in a companion paper by Zarro et al at this meeting; we discuss our predictions in the context of their results.
Program listing for Friday