The structure of interplanetary coronal mass ejections and their solar origins

Interplanetary coronal mass ejection (ICME) models have remained virtually unchanged for over a decade. They do not sufficiently address expansion and evolution or explore the possibility of non-symmetric flux rope geometries. In this dissertation, we develop a new model consistent with both in situ observations of ICMEs and solar models of CMEs. We find that multispacecraft observations of ICMEs more clearly reveal their three-dimensional structure than do observations made by a single spacecraft. When inverted with a versatile non-force-free flux rope model, ICMEs around 1 AU are found to expand predictably in the solar wind, bend along their axial field direction, and have non-circular cross sections. We find force-free magnetic cloud structures maintain their flux rope geometry further out into the heliosphere than do non-cloud CCMEs. The difference between flux ropes arriving at a spacecraft as magnetic clouds or non-cloud structures is the degree of distortion they incur as they travel outward. We determine that existing models incorrectly describe how CCMEs are topologically connected to the Sun. Fitting flux ropes to ICME observations reveals that the leading field direction of the ropes corresponds to the global polar field direction of the Sun while the axial field lies in the plane of the heliospheric current sheet. This result is contrary to the geometry of existing ICME models, but consistent with the geometry of CME genesis models. Long-term variations of the coronal streamer belt and solar polar field result in long-term variations in the magnetic field signature of ICMEs and these variations are predictable. Variations in the orientation of the coronal streamer belt and reversals of the global polar field of the Sun are also reflected in the predicted field orientations of CMEs ejected from the Sun. We extrapolate the radial sizes, temperatures, and how twisted the ropes are back to 30 R _s using a refined understanding of ICME 3-D structure. We find these relations support observations of CMEs originating in the coronal regions.