The investigators will produce a three dimensional reconstruction of solar wind structures that interact with the Earth. The focus will be on the shape of the structures, the interaction of the structures with the ambient solar wind plasma, and the effect of the structures in modifying embedded solar magnetic fields. Their approach is to upgrade a tomographic technique now in use to investigate the structure of the quiet solar wind in three dimensions. Several remotely sensed datasets will be incorporated in the analysis, and the results will be checked against densities, velocities, and magnetic fields measured in situ by spacecraft where data are available.