Time-Dependent Tomography of the Non-Stationary Corona with Multi-Spacecraft Image Data

Solar rotational tomography (SRT) is a 3D image reconstruction method that uses the multiple view-angles provided by solar rotation to ``undo" the line-of-sight integrals that relate white-light coronagraph or EUV images to the underlying 3D structure of the corona. The major difficulty associated with this method is that the structure of the corona can change significantly during the time period required for the Sun to rotate through a large enough range of angles to permit reconstruction. While previous approaches to SRT have assumed a static corona, a new formulation based on Kalman filtering does not make this assumption. Instead, the Kalman filter creates a time-dependent, 3D reconstruction. This method shows much promise for improvement over the static method and is particularly well-suited to take advantage of the view-angles provided the STEREO mission combined with the near-Earth missions. Time-dependent reconstructions from multiple spacecraft are simulated and compared to static reconstructions. Consequences for coordinated observations involving STEREO, SOHO, Solar-B, SDO and the Mauna Loa are discussed.