3D Differential Emission Measure of the 2008 Solar Minimum Corona with Dual-Spacecraft EUVI/STEREO Tomography

We have recently developed solar rotational tomography (SRT) of EUV image time series for the empirical determination of the three-dimensional (3D) distribution of the differential emission measure (DEM) of the global corona. Using this technique, we present a 3D tomographic reconstruction of the local DEM (which also yields the electron density) of the global solar corona between 1.03 and 1.25 Rs for Carrington Rotation 2077 (starting 2008 November 20). The reconstructions were performed using simultaneous STEREO A and B spacecraft EUVI data in the 17.1, 19.5, 28.4 and 30.4 nm bands. At this time, the positions of the two spacecraft were separated by about 90°, which allowed for the EUV reconstruction to be performed in about 3/4 of a solar rotational time instead of a full Carrington rotation, which improved the time resolution of the technique. We complement this reconstruction with a simultaneous potential field source-surface (PFSS) reconstruction of the magnetic field. During this period there were only two important active regions (ARs), and the corona was dominated by a large scale bipolar structure. We show both the full 3D results as well as the azimuthally averaged 2D results, excluding the ARs. The comparison of the 2D results among the tomographic local DEM and the PFSSM results, allows for the construction of a large scale quantitative semiempirical model of the geometry and thermodynamical properties of the equatorial streamer and subpolar regions of the solar minimum corona.