Archive for sun’s atmosphere

gigantic hole in the Sun’s atmosphere has opened up and a broad stream of solar wind is flowing out of i

Posted in 2015, astronomy, Galaxy with tags , , , , , , , on October 15, 2015 by MARIE EMMANUELLE QUILICHINI

Coronal_Hole_sun

NOAA forecasters estimate a 65% of polar geomagnetic storms today as Earth moves deeper into the solar wind stream

A gigantic hole in the sun’s atmosphere has opened up and a broad stream of solar wind is flowing out of it. This is called a “coronal hole.” It is the deep blue-colored region in this extreme UV image from NASA’s Solar Dynamics Observatory

Coronal holes are places in the sun’s atmosphere where the magnetic field unfurls and allows solar wind to escape. In the image above, the sun’s magnetic field is traced by white curving lines. Outside the coronal hole, those magnetic fields curve back on themselves, trapping solar wind inside their loops. Inside the coronal hole, no such trapping occurs. Solar wind plasma is free to fly away as indicated by the white arrows.

For much of the next week, Earth’s environment in space will be dominated by winds flowing from this broad hole. This should activate some beautiful Arctic auroras. NOAA forecasters estimate a 65% of polar geomagnetic storms today as Earth moves deeper into the solar wind stream. Aurora alerts: text or voice

http://www.spaceweather.com/archive.php?view=1&day=14&month=10&year=2015

 

CORONAL HOLES: NASA’s Solar Dynamics Observatory is monitoring a pair of coronal holes straddling the sun’s equator.

Posted in 2014 with tags , , , , , , , on April 10, 2014 by MARIE EMMANUELLE QUILICHINI

 They are the deep-blue wedges in this extreme ultraviolet image of the sun taken mid-day on April 9th:

Coronal holes are places in the sun’s atmosphere where the ambient magnetic field opens up and allows solar wind to escape. A double-stream of solar wind flowing from these coronal holes could reach Earth on April 12-14.

It is possible that neither stream will be geoeffective as they flow north and south of our planet. On the other hand, a “brush pass” might still spark polar auroras. NOAA forecasters estmate a 40% chance of polar geomagnetic storms when the streams arrive. Aurora alerts:textvoice

http://spaceweather.com/

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