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Two years ago, we published "Beautiful Candle Flame Cusp on the Limb" and have been yearning ever since for a worthy on-disk counterpart. That day has finally come, brought to us by Active Region 12035 (just right of center). In addition to being aesthetically pleasing, cusp loops are beloved by scientists because they're thought to be tell-tales signs of magnetic reconnection, an energetic phenomenon that is ubiquitous on the Sun but often difficult to pinpoint. Magnetic field lines momentarily intersect and reconfigure above the cusp, releasing energy and producing a sunward plasma flow along the arch. This heats the cusp enough to produce the X-ray emission seen here, which can last for several hours as new field lines are continously forced into the reconnection site. Based on how diffuse the cusp is in this image, we're probably catching it after its fully glory. But as the saying goes, it's better to have seen a decaying cusp than to have seen no cusp at all.
Keywords: Cusp, Full Disk
Filters: Be_thin, Al_poly