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[1] The Solar Mass Ejection Imager (SMEI) has been tracking coronal mass ejections (CMEs) from the Sun to the Earth and beyond since it came online in February 2003. This paper presents some results from the first 19 months of data from SMEI, when over 140 transients of many kinds were observed in SMEI's all-sky cameras. We focus specifically on 20 earthward directed transients, and compare distance-time plots obtained from the SMEI transients with those observed in halo CMEs by Large-Angle Spectrometric Coronograph (LASCO) aboard Solar and Heliospheric Observatory (SOHO), and the arrival time of the shock observed by ACE at 0.99 AU. The geometry of one particular transient is compared using both LASCO and SMEI images in a first attempt to investigate geometry evolution as the transient propagates through the interplanetary medium. For some events, the halo CME, SMEI transient, and shock at 0.99 AU do not match, suggesting that some transients may not correspond to a halo CME. Finally, an evaluation of the potential of SMEI to be used as a predictor of space weather is presented, by comparing the transients observed in SMEI with the 22 geomagnetic storms which occurred during this timeframe. A transient was observed in 14 cases, and distance-time profiles would have allowed a prediction of the arrival time at ACE within 2 hours of its actual arrival for three events, and within 10 hours for eight events. Of these eight events, seven were detected by SMEI more than 1 day before the transient's arrival at the Earth.

Two coronal mass ejections (CMEs) are presented which were tracked through the LASCO field of view (FOV ) within 30 R and later as interplanetary CMEs (ICMEs) through the SMEI FOV from 80 to 150 R . They were also associated with erupting filaments observed by EIT, providing information on trajectory of propagation. This allowed three-dimensional reconstructions of CME /ICME geometry, along with corrected (not sky plane projected) measurements of distance-time (DT) plots for each event to $0.5 AU. An investigation of morphology was conducted. The results suggest that fine structures of the CMEs are eroded by the solar wind, and curvature becomes more sharply convex outward, suggesting that ICME footpoints remain fixed to the Sun even at 0.5 AU. We also present two models describing the evolution of CMEs/ICMEs at large distances from the Sun (far from the launch mechanism and effects of gravity and solar pressure) and consider two drag models: aerodynamic drag and snowplow. There was little difference between these, and their DT profiles matched well with the SMEI data for event 1. Event 2 showed a net acceleration between the LASCO and SMEI FOVs and we could match the data for this event well by introducing a driving Lorentz force. ICME mass almost doubled as a result of swept-up solar wind material from the snowplow model. Finally, we compared the geometry and kinematics of the ICME with that produced by the HAFv2 model and found that the model reasonably matched the geometry, but overestimated the ICME speed. Subject headingg s: interplanetary medium -solar-terrestrial relations -solar windSun: coronal mass ejections (CMEs)

We are investigating the geometric and kinematic characteristics of interplanetary coronal mass ejections (ICMEs) using data obtained by the LASCO coronagraphs, the So-STEREO Science Results at Solar Minimum lar Mass Ejection Imager (SMEI), and the SECCHI imaging experiments on the STEREO spacecraft. The early evolution of CMEs can be tracked by the LASCO C2 and C3 and SEC-CHI COR1 and COR2 coronagraphs, and the HI and SMEI instruments can track their ICME counterparts through the inner heliosphere. The HI fields of view (4 -90°) overlap with the SMEI field of view (> 20°to all sky) and, thus, both instrument sets can observe the same ICME. In this paper we present results for ICMEs observed on 24 -29 January 2007, when the STEREO spacecraft were still near Earth so that both the SMEI and STEREO views of large ICMEs in the inner heliosphere coincided. These results include measurements of the structural and kinematic evolution of two ICMEs and comparisons with drive/drag kinematic, 3D tomographic reconstruction, the HAFv2 kinematic, and the ENLIL MHD models. We find it encouraging that the four model runs generally were in agreement on both the kinematic evolution and appearance of the events. Because it is essential to understand the effects of projection across large distances, that are not generally crucial for events observed closer to the Sun, we discuss our analysis procedure in some detail.

[1] The Solar Mass Ejection Imager (SMEI) on the Coriolis spacecraft has been obtaining white light images of nearly the full sky every 102 minutes for three years. We present statistical results of analysis of the SMEI observations of coronal mass ejections (CMEs) traveling through the inner heliosphere; 139 CMEs were observed during the first 1.5 years of operations. At least 30 of these CMEs were observed by SMEI to propagate out to 1 AU and beyond and were associated with major geomagnetic storms at Earth. Most of these were observed as frontside halo events by the SOHO LASCO coronagraphs.