NASA: Coronal Hole Is Rotating Into View –“Spews Streams of High Speed Solar Wind Into Space”




A substantial coronal hole began to rotate into view over the past few days (Dec. 1 – 2, 2016). Coronal holes are magnetically open areas of the sun's magnetic field structure that spew streams of high speed solar wind into space. In about a week or so that coronal hole might send streams of particles in the direction of Earth. Often times these streams can interact with Earth's magnetosphere and generate aurora. The images were taken in a wavelength of extreme ultraviolet light.

Coronal holes are regions where the sun's corona is dark. These features were discovered when X-ray telescopes were first flown above the Earth's atmosphere to reveal the structure of the corona across the solar disc. Coronal holes are associated with 'open' magnetic field lines and are often found at the sun's poles. The high-speed solar wind is known to originate in coronal holes. The solar wind escaping from this hole will reach Earth

The magnetic field of a coronal hole is different than the rest of the Sun. Instead of returning to the surface, these magnetic field lines stay open and stretch out into space. At the moment we do not yet know where they reconnect. Instead of keeping the hot gas together, these open magnetic field lines cause a coronal hole to form, where solar wind can escape at high speeds.

When a coronal hole is positioned near the centerof the Earth-facing solar disk, these hot gasses flow to Earth at a higher speed than the regular solar wind and cause geomagnetic disturbances on Earth with enhanced auroral activity on high latitudes. Depending on the size and location of the coronal hole on the disk, more or less auroral activity can be expected.

The Daily Galaxy via Solar Dynamics Observatory, NASA.

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