Parameter Tree:
EARTH SCIENCE > SUN-EARTH INTERACTIONS > SOLAR ACTIVITY > CORONA HOLES

Definition:
An extended region in the solar corona where the density and temperature are
lower than other places in the corona. The weak diverging and open magnetic
field lines in coronal holes extend radially outward and do not immediately
return to the sun. The high speed part of the solar wind comes from coronal
holes.
Reference: the Cambridge Encyclopedia of the Sun, The Cambridge University
Press,
Cambridge, CB2, 2RU, UK, 2001.


Reference:
From: NASA/MSFC Solar Physics:
http://wwwssl.msfc.nasa.gov/ssl/pad/solar/feature3.htm