Automatic Recognition of Complex Magnetic Regions on the Sun using GONG Magnetogram Images and Their Usefulness in Predicting Flares

Global Oscillation Network Group (GONG) magnetograms can be used to automatically identify active regions associated with sunspots and flares by thresholding of line-of-sight component of the solar magnetic field. Once these regions are identified, they can be useful in predicting flare potential by locating strong-gradient polarity inversion lines (SPILs). To a trained eye, the inversion line analysis of an active region can be drawn on to estimate the flare probability. With this aim in mind, a well-known pixel shifting technique is used to automatically find the SPILs. Then a measure of curvature along the SPIL is calculated. By this means, a steepness of the gradient value is obtained and used as a proxy for the expected strength of the flare, while the curvature measured along the SPILs is related to the flare potential. The GONG magnetograms are produced 24 hours a day seven days a week providing an opportunity for near real-time flare warning capability. The techniques used to locate active regions are uncomplicated to implement and can also be used to identify regions of interest for an automatic analysis of H-alpha images.