Io's volcanism influences Jupiter's magnetosphere

Volcanic emissions from Jupiter's moon Io supply plasma to the planet's magnetosphere and lead to its main auroral emissions. New observations show that the main auroral oval expanded and outer emissions brightened in spring 2007. Some studies have suggested that magnetospheric changes such as these could be caused by changes in the incoming solar wind. Bonfond et al. present several lines of evidence—including images from the Hubble Space Telescope and observations of a volcanic plume on Io from the New Horizons probe along with measurements of increased emissions from Jupiter's sodium cloud—that indicate that Io's volcanism controls changes in Jupiter's magnetosphere. (Geophysical Research Letters, doi:10.1029/2011GL050253, 2012)