GONG Synoptic Magnetograms and Coronal Magnetic Field Modeling

Line-of-sight photospheric magnetograms are produced every minute at GONG's six sites. All modulators and driving circuitry have recently been replaced, improving the sensitivity, accuracy and zero point by orders of magnitude. Information on the solar atmospheric field can most reliably be derived from such photospheric data, from which model coronal fields are then extrapolated. Near-real-time synoptic magnetogram are produced by GONG every hour. Potential-field source-surface (PFSS) models are then produced every hour yielding insight into large-scale coronal field changes caused by quasi-static evolution and by flares and coronal mass ejections. We also provide a synoptic map and model summarizing each integral Carrington rotation. Features highlighted in the plots and movies include coronal holes, the streamer belt, magnetic flux open to the ecliptic plane and large-scale changes in the field topology. GONG is the official provider of magnetograms for NASA's STEREO mission.