30 Mai 2013 adminFrumam – D. Vibert (LAM) : Solar Rotational Tomography : reconstruction of the electronic density in the Solar Corona.Carte non disponible Date/heure Date(s) - 30/05/201314 h 00 min - 15 h 00 min Catégories Pas de Catégories Solar Rotational Tomography: reconstruction of the electronic density in the Solar Corona. By D. Vibert, LAM Abstract: I will describe the concept of SRT applied to white light coronographic images and then focus on the time variation problem. The usual assumption is that the corona is almost stable during one rotation so that a static tomography can be achieved. This is strongly not valid near the sun and I will show different techniques we developed to address this issue. This problem is largely ill-posed by nature and taking into account the time variation without increasing the size of the observed data set leads to a massively undetermined problem needing a strong amount of regularization. The emergence of efficient L1-norm minimization algorithm targeting large scale problems without loosing too much accuracy let us apply a proximal splitting method to achieve a TV spatio-temporal regularization of the least-square solution.