4 Iyar 5772
Day 19 of the Omer
Spaceweather.com reports the following:
CHANCE OF FLARES: Sunspot AR1465 has developed a 'beta-gamma-delta' magnetic field that harbors energy for X-class solar flares. Because of the sunspot's location near the middle of the solar disk, any eruptions will likely be Earth-directed.
QUIETING STORM, MORE TO COME: Earth's magnetic field is quieting after two straight nights of mild to moderate geomagnetic storms. At the height of the disturbance on April 23-24, auroras were spotted in more than a dozen US states including Michigan, Nebraska, Kansas, Wisconsin, North Dakota, South Dakota, Iowa, Illinois, Minnesota, and Colorado. On the threshold of the Arctic Circle in Anchorage, Alaska, the Northern Lights pierced the glow of the midnight sun.
Here is some additional sun news that will make up part of my upcoming report on What is Really Going on With "2012."
(Spacedaily.com) Approximately every 11 years the magnetic field on the sun reverses completely - the north magnetic pole switches to south, and vice versa. It's as if a bar magnet slowly lost its magnetic field and regained it in the opposite direction, so the positive side becomes the negative side.
But, of course, the sun is not a simple bar magnet and the causes of the switch, not to mention the complex tracery of moving magnetic fields throughout the eleven-year cycle, are not easy to map out. This flip coincides with the greatest solar activity seen on the sun in any given cycle, known as "solar maximum." Currently the polarity at the north of the sun appears to have decreased close to zero - that is, it seems to be well into its polar flip from magnetic north to south - but the polarity at the south is only just beginning to decrease.
"Right now, there's an imbalance between the north and the south poles. The north is already in transition, well ahead of the south pole, and we don't understand why." The asymmetry described in recent research papers belies models of the sun that assume that the sun's north and south polarities switch at the same time. In addition, both papers agree that the switch is imminent at the north pole, well in advance of general predictions that solar maximum for this cycle will occur in 2013.
Lastly, the direct Hinode results also suggest a need to re-examine certain other solar models as well. Measuring the magnetic activity near the poles isn't easy because all of our solar telescopes view the sun approximately at its equator, offering only an oblique view of the poles, when they require a top-down view for accurate magnetic measurements.
It was discovered in 2003 that as the sun moves toward solar maximum, giant eruptions on the sun, called prominence eruptions - which during solar minimum, are concentrated at lower solar latitudes - begin to travel toward higher latitudes near the poles.
In addition, the polar brightness in the microwave wavelengths declines to very low values. "These prominence eruptions are associated with increased solar activity such as coronal mass ejections or CMEs, so CMEs originating from higher latitudes also point to an oncoming solar maximum. When we start to see prominence eruptions above 60 degrees latitude on the sun, then we know that we are reaching solar maximum." By mapping the brightness of microwave radiation throughout the chromosphere, the scientists showed that the intensity at the north pole has already dropped to the threshold that was reached in the last solar maximum cycle, suggesting the onset of solar max there. This is backed by the fact that prominence eruptions are also occurring at high latitudes in the north.
Eruption activity in the south half of the sun, however, is only just beginning to increase - the first CME occurred there in early March 2012. The Hinode data also shows this discrepancy between the north and the south. The magnetic map of the poles of every month since September of 2008 showed large, strong concentrations of magnetic fields that are almost all magnetically negative in polarity. Recent maps, however, show a different picture. Not only are the patches of magnetism smaller and weaker, but now there is a great deal of positive polarity visible as well. 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 the first direct observation of this field reversal. And it is extremely important to understanding how the sun's magnetism generates the solar cycle." Typical models of the magnetic flip, suggest that as active regions rotate around the equator, their higher, trailing edge - which is almost always the opposite polarity from the pole in their hemisphere - drift upward, eventually dominating the status quo and turning positive to negative or negative to positive.
The Hinode data show that this transition at the north began BEFORE such drifting had a chance to occur. "This is one of the most interesting things in this Hinode paper to me. 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?" The idea that asymmetries exist in the sun is not completely new. Other work has recently emphasized symptoms of this asymmetry, measuring, for example, more sunspots in the northern hemisphere than in the south at the moment. "But most of the well-developed models don't incorporate the asymmetry in them. More complicated models that incorporate asymmetries do exist, but they have other ways in which they fail to match observations."
Scientists will 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.
Or it could be something else entirely - like a Super-Max Cycle as proposed by Patrick Geryl.
7 hours ago