Monitoring Active Region Development on the Far Side of the Sun

Magnetic regions in the Sun’s outer atmosphere exert major impacts on space weather in the near-Earth environment. Near-term impacts at Earth are predominantly due to magnetic regions in the Sun’s near hemisphere; however, because the Sun rotates, mag- netic regions in the far hemisphere cross into the near hemisphere with little warning—except for our ability to monitor the Sun’s far hemisphere from vantages in the helio- sphere other than that of Earth. For the past several years NASA’s twin STEREO spacecraft have been in positions to view the entirety of the far hemisphere from the far side of the solar system. We are now approaching a period of most of a decade in length during which STEREO coverage of the Sun’s far hemisphere will be greatly diminished or nil. We have developed algorithms capable of analyzing seismic observations of the Sun’s near hemisphere to map large active regions with full coverage of the Sun’s far hemisphere. We propose to use these algorithms to produce a data product of synoptic seismic maps of the Sun’s far hemisphere that can take over the role of STEREO in the service of our nation’s space-weather forecasting needs.