Wednesday, October 28, 2015


SOLAR SECTOR BOUNDARY CROSSING: High-latitude auroras are possible on Oct. 29th when Earth crosses through a fold in the heliospheric current sheet. This is called a "solar sector boundary crossing," and NOAA forecasters estimate a 30% chance of polar geomagnetic storms when it occurs.

LONG RANGE AURORA FORECAST: On Oct. 7th and 8th, a high-speed stream of solar wind hit Earth's magnetic field, sparking strong geomagnetic storms and auroras. On Nov. 2nd - 5th, it could happen again. The same solar wind stream that caused the October storms is set to return during the first week of November. It is flowing from this hole in the sun's atmosphere:

Image credit: NASA/Solar Dynamics Observatory. Oct. 28, 2015.

The dark circled region, called a "coronal hole," is where the sun's magnetic field has opened up, allowing solar wind to escape. The last time this particular coronal hole turned toward Earth, in early October, it lashed our planet's magnetic field with an 800 km/s solar wind stream. Now it is turning toward Earth again. Aurora fans, mark your calendar for the first week of November. You might see something like this.

Taken by johnny henriksen on October 7, 2015 @ HARSTAD, Troms, Norway 

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