Sunspot 484

[ku4a]

I understand that Sunspot 484, which I believe is on the visible side of the sun, is one of the biggest sunspots in years. Is a large sunspot good or bad? I.e., is it more likely to flare and cause geomagnetic disturbances, or just increase the F-layer ionoization nicely and give us higher MUFs?

[ku4a]

http://www.foxnews.com/story/0,2933,100981,00.html

Looks like I got the answer to my question at least for now.

[NW7US]

http://www.foxnews.com/story/0,2933,100981,00.html

Looks like I got the answer to my question at least for now.

I don't think that this news story fully explores the current event. The latest warning/alert forecast for this is as follows:

(From NOAA):

Code: Select all

Forecast for next 24 hours:

Space weather for the next 24 hours is expected to be minor.
Geomagnetic storms reaching the G1 level are expected.
Radio blackouts reaching the R1 level are expected.


This takes into account that the IMF is mostly oriented toward the north. When this is oriented south (Bz is negative), then it will affect the geomagnetic field. But, if north (Bz is positive), then it will not affect the geomagnetic field.

When the CME glances the Earth's magnetosphere, the IMF has to be south (Bz negative), if it were to cause a geomagnetic storm. The thinking at this time is that the Bz will not go negative, or if it will, it will not go very far. Thus, the geomagnetic activity level should not go too high, at most minor storm level during the late afternoon and early evening of the 24th (local time).

By the way, the large sunspot is not the cause of geomagnetic storms. The IMF and solar wind speed, along with enhancements from CMEs, cause geomagnetic storminess. If the sunspot group throws a flare, however, we might have a short radio blackout.

The forecast is for minor to moderate flaring.