SAFARI: Solar Activity Far Side Investigation

The Solar Activity Far Side Investigation, or SAFARI, is a small mission concept, or an element of a larger mission, devoted to exploring the origins of solar magnetic activity by carrying out observations of the velocity and magnetic fields at the solar surface from a vantage point widely separated from Earth in longitude and latitude. SAFARI images the Sun from orbits trailing/leading the Earth at 1 AU (SAFARI-S), with important excursion in latitude, while at the same time the Sun is imaged from the Earth (SAFARI-E). SAFARI carries out these observations using a compact Doppler magnetograph based on a simple, robust design with magneto-optical filters. SAFARI’s ground based component, SAFARI-E, uses a similar observational technique, allowing precise inter-calibration of magnetograms and providing an opportunity to implement the novel technique of stereoscopic helioseismology, probing flows and structural heterogeneities deep in the convection zone, reaching below the tachocline and opening a new observational window into the Sun. The combined measurements of solar magnetic fields from Earth and spacecraft viewpoints extends the longitudinal and latitudinal coverage of the solar disk allowing extended simultaneous observations permitting the full study of active region development and decay that cannot be observed in its entirety from a single point due to solar rotation. In addition, the structure and depths of sunspots can be addressed with stereoscopic local helioseismology. Combined scalar magnetic field measurements from multiple vantage points provide the vector magnetic field; combined LOS velocity field measurements frm different vantage points provide the vector velocity field: fundamental measurements to understand solar activity.