SUVI Sees a Solar Flare
On Tuesday, April 18, 2017, the Solar Ultraviolet Imager (SUVI) on GOES-16 observed a large solar eruption linked to a C5 class solar flare. C-flares are moderate events without a lot of impact on space weather near Earth, but the eruption itself was a large and dramatic one that might have had some space weather consequences had it been directed towards Earth. Instead, the eruption blasted harmlessly into interplanetary space far from Earth, but the location where it occurred, just on the limb of the Sun, gave SUVI a fabulous view of the event.
Large eruptions like this one can cause large-scale restructuring of the sun's magnetic field. In these movies you can see just how this happens, as solar magnetic field loops, filled with million-degree solar plasma, are first opened up by the eruption and eventually close back down again. We see a large darkening near the eruption as material from the sun's atmosphere pours out into space, and a subsequent re-brightening as that material is slowly replenished afterward. We also see another classic signature of solar eruptions, so-called post-flare loops, an arcade of glowing magnetic loops that form in the wake of the eruption. These are brand new magnetic field structures, formed by the very processes that extract stored energy in the sun's magnetic field that power both the eruption and bright flare that accompanies it.