Reconstruction of three-dimensional structure of coronal mass ejections using SOHO and STEREO polarimetric observations

We present reconstructions of coronal mass ejections (CMEs) from SOHO and STEREO polarimetric observations. Polarimetry of CME scattered white light provides information on the density distribution along the line of sight. Reconstructions of the three-dimensional (3D) structure of several halo CMEs observed with SOHO show a bilateral symmetry, which we interpret as an expanding magnetic flux loop arcade. We combine measurements from the STEREO A and B spacecraft spacecraft to determine the three-dimensional positions of several points in the eruptions using both parallax and polarimetric techniques. In addition, we determine the gross 3D density distribution and direction of several CMEs.