Sunspot region 2740, C9.9 solar flare

Monday, 6 May 2019 17:08 UTC

Why is this fairly unimpressive sunspot region popping with C-class solar flares here and there? Well, it's the magic that is magnetic reconnection at work. We get back to the C-class solar flares later but first lets look at sunspot region 2740 with the help of the images below. First we see sunspot region 2740 (and an unnumbered friend that is just rotating into view) in white light and a magnetogram of this region. The arrow indicates a magnetic delta structure and that magnetic delta structure is for a sunspot region what would be a bad fitting shoe to us. Something that gets you pretty damn upset and angry as your toes are all bunched up. Sort of. You get the point. But more specifically, a magnetic delta structure is the umbrae of opposite polarity in a single penumbra. Opposite magnetic fields so close by each other causes magnetic tension and reconnection (resulting in solar flares) and that is what we are seeing in sunspot region 2740. The solar flares have been fairly impulsive (short in duration) thus far and have not yet reached the M-class threshold but this region remains a threat you should keep your eyes on!

Image: SDO/HMI white light.

Image: SDO/HMI magnetogram.

C9.9 solar flare

This morning's C9.9 solar flare was just one of five C-class solar flares today with the C9.9 and a C7.3 solar flare being the two strongest events today thus far. None of these solar flares produced a coronal mass ejection (a cloud of solar plasma) into space with an earth-directed component but there are a couple of very minor coronal mass ejections to be seen both on the coronagraph images from STEREO Ahead and SOHO. All of these plasma clouds are very minor but it is a sign of potential that it can release plasma into space despite the fairly minor strength of these flares compared with M or even X-class solar flares. Another reason to keep your eyes on this sunspot region as in just two to three days from now this region will face earth head-on.

Animation: coronal mass ejections seen today on SOHO LASCO C2.