Coronal Hole

An area of the corona that appears dark when viewed in ultraviolet light. They are usually located around the poles of the Sun, but can occur at other latitudes as well. The magnetic field lines in a coronal hole extend out into the solar wind rather than coming back down to the Sun’s surface. Because the magnetic field lines extend into space, they carry hot material with them and leave patches of the solar surface cooler.

An area of the corona which appears dark in X-rays and ultraviolet light. They are usually located at the poles of the Sun, but can occur in other places as well. The magnetic field lines in a coronal hole extend out into the solar wind rather than coming back down to the Sun's surface as they do in other parts of the Sun.

In solar-terrestrial terms, an extended region of the corona, exceptionally low in density and associated with unipolar photospheric regions.