The second of two expected CMEs struck the magnetosphere at 0318z this morning, passing ACE
at just before 0230z, with much more density than was predicted
but still a moderate speed. There was a response from the auroral oval since then but planetary geomagnetic activity (from magnetometers) doesn't seem high, so not really much of a reverberation going on and hence no aurora forecast. Levels are still unsettled though, so it might be worth keeping an eye on Kiruna
later this evening to see what we're rotating toward.
In the longer term, a study of SOHO and Hinode data by separate teams has detected the degeneration in the magnetic field of the Sun in the northern hemisphere. Possible indications that the magnetic flip, and signal of the Solar Maximum, is imminent and much earlier than the 2013 prediction. The net result would be a smaller cycle than suggested, and less chance for eruptive prominences at geoeffective lower solar latitudes as they now start to migrate up the sun's face and eject their danger upward. Still, the activity in the southern hemisphere is still increasing overall, and the studies suggest this hemisphere (and pole) is slower to enter the Maximum than the northern hem. These studies cast a great deal of doubt on the validity of current solar models, most of which are based largely upon activity at lower solar latitudes and don't account for the observed asymmetric magnetic field reversal progression.
What once pointed to a strongly negative north pole, is now a weakly magnetized, mixed pole that will become neutral – which occurs at solar maximum -- within the month according to the team's predictions.
"This is one of the most interesting things in this Hinode paper to me," says Tarbell. "How did the polar reversal start so early, even though the onset of the solar cycle, that is, increased activity at lower latitudes, hadn't begun yet?"
Scientists will also keep their eye on the current cycle – numbered Solar Cycle 24 – because a polar switch at the north that is sooner than was expected also implies this may be a fairly small cycle in terms of the number of sunspots and amount of solar activity.