Three Coronal Holes
Jet Propulsion Laboratory https://www.jpl.nasa.gov/ April 16, 2018
For much of this week the sun featured three substantial coronal holes (Apr. 3-6, 2018). Coronal holes appear as large dark areas which are identified with arrows in the still image. These are areas of open magnetic field from which high speed solar wind rushes out into space. This wind, if it interacts with Earth's magnetosphere, can cause aurora to appear near the poles. They are not at all uncommon.
Movies
PIA22414_3_coronal_holes_big.mp4
PIA22414_3_coronal_holes_sm.mp4
SDO is managed by NASA's Goddard Space Flight Center, Greenbelt, Maryland, for NASA's Science Mission Directorate, Washington. Its Atmosphere Imaging Assembly was built by the Lockheed Martin Solar Astrophysics Laboratory (LMSAL), Palo Alto, California.