Comparison of ICME Leading Edge Orientations Determined by Single Spacecraft Techniques

In this investigation we examine the leading edge orientation and morphology of ICMEs observed by interplanetary spacecraft. In particular we compare and contrast three independent techniques for determining this leading edge orientation. First, if a magnetic cloud is associated with an ICME then it is possible to fit a constant alpha, force-free magnetic flux rope model to the data. This allows the determination of axis orientations and chiralities. If planar magnetic structures are present in the sheath region, general ahead of faster ICMEs, then the orientations of these planes give insights into the axis orientation and the shape of the leading edge of the ICME. Finally, examining plasma flow deflections, again in the sheath region, will also give clues to the cross-sectional morphology as the deflections are linked to the leading edge morphology of the ICME and its axis orientation.