coronal hole


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coronal hole

[kə′rō·nəl ‚hōl]
(astronomy)
A large-scale, apparently open structure in the solar corona, devoid of any soft x-ray emission and surrounded by diverging boundary structures.
References in periodicals archive ?
"Last night's aurora was driven by a fast solar wind coming from a coronal hole. The solar wind is a plasma, or electrically charged gas, that constantly blows out from the sun.
Energy losses (in erg [cm.sup.-2][s.sup.-1]) from the chromosphere and the corona (12) Region Quiet Sun Coronal hole Coronal temperature [K] 1.1-1.6 x [10.sup.6] [10.sup.6] Coronal energy loss 3 x [10.sup.5] 8 x [10.sup.5] Chromospheric energy 4 x [10.sup.6] 4 x [10.sup.6] loss Region Active region Coronal temperature [K] 2.5 x [10.sup.6] Coronal energy loss [10.sup.7] Chromospheric energy 2 x [10.sup.7] loss
They registered, in fact, coronal hole jets, with speeds of 94 to 760 km [s.sup.-1] and lifetimes of the order of several tens of minutes.
The improved chances of a sighting this week were down to the combined effect of a "coronal hole" near the Sun's equator, which had aligned with Earth and was sending high-speed solar winds to buffet the planet, and the time of year.
WASHINGTON (CyHAN)- A coronal hole, almost square in its shape, is one of the most noticeable features on the Sun of late (May 5-7, 2014).
Washington, Oct 16 ( ANI ): Researchers have found evidence that magnetic waves in a polar coronal hole contain enough energy to heat the corona and that they also deposit most of their energy at sufficiently low heights for the heat to spread throughout the corona.
Similar low-speed winds have been identified from the CAT analysis of our IPS observations over the pole at solar maximum, when the polar coronal hole shrinks in size before and after its disappearance.
Hahn's team also calculated that the energy dissipated could provide up to 70% of that needed to heat the polar coronal hole and accelerate the fast solar wind.
Another coronal hole high speed stream caused a minor geomagnetic storm on Feb.
The coronal hole leaves an open channel out of which the solar winds blast out.
SUN/CORONAL HOLE: A coronal hole, almost square in its shape, is one of the most noticeable features on the Sun of late (May 5-7, 2014).