"heliophysics"

"A few years ago, scientists coined the term "heliophysics" to describe the emerging science of the sun-Earth system. As a nod to the importance of the topic, NASA has set up a dedicated Heliophysics Division at HQ in Washington DC, and the United Nations declared 2007 the "International Heliophysical Year" (IHY) in hopes of spurring global involvement in this new field."

Reference: here!

Also take a look at wikipedia!