A CONVERGING FLUX MODEL OF AN X-RAY BRIGHT POINT AND AN ASSOCIATED CANCELING MAGNETIC FEATURE

X-ray bright points are an important part of the solar corona and ther efore of the coronal heating problem. When it was first realized that bright points are always situated above opposite polarity magnetic fra gments in the photosphere, it was natural to suggest that such fragmen ts represent emerging flux and that an X-ray bright point is caused by reconnection of the emerging flux with an overlying coronal magnetic field. However, a recent important discovery at the Big Bear Solar Obs ervatory is that the magnetic fragments of opposite polarity are usual ly not emerging but are instead coming together and disappearing and s o are referred to as canceling magnetic features. Sometimes a tiny fil ament is observed to form and erupt at the same time. A unified model is here proposed which explains these observational features and has s everal phases: 1. a preinteraction phase, in which two photospheric fr agments are unconnected magnetically and begin to approach one another , until eventually oppositely directed fields from the fragments come into contact at a second-order null point; 2. an interaction phase, in which the null point becomes an X-point and rises into the corona; an X-ray bright point is created for typically 8 hr by coronal reconnect ion, driven by the continued approach of the photospheric sources; lon g hot loops and Yohkoh X-ray jets may be created by the reconnection, and rapid variability in bright point emission may be produced by an i mpulsive bursty regime of reconnection; the explosive events seen with HRTS may be produced as the X-point passes through the upper chromosp here; 3. a cancellation phase, in which a canceling magnetic feature i s produced by photospheric reconnection as the fragments come into con tact and decrease in strength; above the canceling fragments a small f ilament may form and erupt over typically an hour. An important role i s played by the interaction distance (d), which is proportional to the magnetic flux of the fragments and inversely proportional to the over lying magnetic field strength. It determines the fragment separation a t which the interaction phase begins and the resulting maximum height of the reconnection point. It is suggested that coronal reconnection d riven by footpoint motion represents an elementary heating event that may be heating normal coronal loops and may be at the root of the nano flare/microflare process. Bright points may well be at the large-scale end of a broad spectrum of events of the type modeled in this paper, which are heating the solar corona. At very small scales, such events in ''furnaces'' in the coronal hole network may even produce high-freq uency waves that propagate out and drive the solar wind (Axford 1993).