Team discovers 'throttle' for solar wind

These are false-color images of ultraviolet light emitted by the solar atmosphere taken with SOHO's Extreme-ultraviolet Imaging Telescope. Note how more structures appear in the atmosphere as the solar maximum of 2000 approaches, from the left image in early 1997 to the right image in late 1999. These changing structures regulate the escape of helium in the solar wind. Image courtesy: ESA and NASA