Limitations in the Use of Ha Filament and Fibril Activity as a Short-Term (30-Minute) Predictor of Flares and Flare-Like Events

摘要

A contingency matrix showing the relationship between flares and H alpha filament or fibril activity is presented for one active region (NOAA 3221, 20-28 July 1981). Activity in a filament or fibril was defined to exist whenever these structures became visible at H alpha + or - 1A (visibility at these wavelengths is due to mass motions, and may or may not signify the onset of a flare). A chi square test on the observed matrix distribution rejects the null hypothesis at the 0.001 level. Thus the data support the concept of filament activity flare association as a true physical phenomenon, although the association between these two variables is not observed to be sufficiently strong to render it useful as a short term flare predictor. Most of the flare events in this study were smaller than subflare class. Nevertheless, the same approximate degree of association was observed between these small flares and their pre flare filament activity as has been found in studies of major flares. The result suggests that the filament activity flare association is probably universal and applies to flare activity on very small scales. Keywords: Reprints; Solar flare predictions; Solar fibrils; Solar filaments.