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Submitted on 2014-04-09
Usually, strong solar flares (X-class) are associated to big and complex sunspot groups, reaching maximum areas equivalent to 15 times the surface area of the Earth. That's why it was interesting to see that two recent X-class flares were produced in regions which were much smaller. Indeed, the X-class flares on 25 February and in particular on 29 March this year took place in sunspot regions that hardly reached an area similar to that of the Earth's surface (about 170MH, see Note 1).
Submitted on 2014-04-02
Homologous flares are the solar equivalent of identical twins. They concern a series of solar flares taking place repetitively in the same active region with essentially the same position and with a common pattern of development, i.e. having the same main footpoints and general shape in the main phase as defined in H-alpha or EUV-imagery. Though not a requirement, homologous flares often have similar strength, and if there are more than two, they sometimes occur within similar time intervals.
Submitted on 2014-03-26
We are now more than 5 years in the current solar cycle (SC), and so far we have not experienced a single extreme geomagnetic storm.
Submitted on 2014-03-19
Over the last few weeks, big, complex sunspot groups and associated high flaring activity got everybody's attention. One would almost forget that solar filaments are also part of the solar activity. Time for a change!
Submitted on 2014-03-06
Everybody has noticed it: Over the last few months, solar activity has shifted into a higher gear.
Submitted on 2014-02-27
In a previous news item, it was already discussed how some CMEs use unconventional techniques to get to Earth undetected and create all of a sudden a geomagnetic disturbance.
Guess what? Those sneaky CMEs found a new way to surprise the space weather forecasters!...
Submitted on 2014-02-14
What seemed to be a boring and declining sunspot group suddenly turned out to be the most flare productive group of the week.
On 9 February, NOAA 1974 was a relatively small group with almost no spots in its trailing end. Then, in the course of the day, new magnetic flux emerged in this trailing portion gradually increasing its sunspot area to nearly 6 times the surface area of the Earth by 15 February. In view of the close proximity of the sunspot groups (less than 10 degrees in heliographic longitude), this region was still considered as 1 sunspot group.
Submitted on 2014-02-13
NOAA 1967 has rotated behind the west limb. It was a little bit of a disappointment that the largest sunspot group so far this solar cycle (according to NOAA statistics), only produced numerous M-flares. The approximate positions of 15 of these M-flares, produced between 30 January and 7 February, are indicated on a 2 February SDO-image of NOAA 1967.
Submitted on 2014-02-06
On 27 January, a big, complex region rounded the Sun's east limb and was labelled NOAA 1967. This large sunspot group was the return of NOAA 1944 which appeared early January and was very active at that time, including 7 M- and 1 X-class flare. Using solar eclipse glasses, both groups were easy naked-eye objects.
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