Solar Mass Ejection Imager 3-D reconstruction of the 27-28 May 2003 coronal mass ejection sequence

The Solar Mass Ejection Imager (SMEI) has recorded the inner-heliospheric response in white-light Thomson scattering for many hundreds of interplanetary coronal mass ejections (ICMEs). Some of these have been observed by the Solar and Heliospheric Observatory (SOHO) Large-Angle Spectroscopic Coronagraph (LASCO) instruments and also in situ by near-Earth spacecraft. This article presents a low-resolution three-dimensional (3-D) reconstruction of the 27–28 May 2003 halo CME event sequence observed by LASCO and later using SMEI observations; this sequence was also observed by all in situ monitors near Earth. The reconstruction derives its perspective views from outward flowing solar wind. Analysis results reveal the shape, extent, and mass of this ICME sequence as it reaches the vicinity of Earth. The extended shape has considerable detail that is compared with LASCO images and masses for this event. The 3-D reconstructed density, derived from the remote-sensed Thomson scattered brightness, is also compared with the Advanced Composition Explorer (ACE) and Wind spacecraft in situ plasma measurements. These agree well in peak and integrated total value for this ICME event sequence when an appropriately enhanced (∼20%) electron number density is assumed to account for elements heavier than hydrogen in the ionized plasma.