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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 111, A04105, doi:10.1029/2005JA011349, 2006

Tracking halo coronal mass ejections from 0–1 AU and space weather forecasting using the Solar Mass Ejection Imager (SMEI)

T. A. Howard

School of Physics and Astronomy, University of Birmingham, Edgbaston, UK


D. F. Webb

ISR, Boston College, Chestnut Hill, Massachusetts, USA


S. J. Tappin

School of Physics and Astronomy, University of Birmingham, Edgbaston, UK


D. R. Mizuno

ISR, Boston College, Chestnut Hill, Massachusetts, USA


J. C. Johnston

Space Weather Center of Excellence, Air Force Research Laboratory, Hanscom AFB, Massachusetts, USA


Abstract

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.

Received 3 August 2005; accepted 26 January 2006; published 29 April 2006.

Keywords: CMEs; interplanetary transients; space weather.

Index Terms: 2139 Interplanetary Physics: Interplanetary shocks; 2101 Interplanetary Physics: Coronal mass ejections (7513); 2169 Interplanetary Physics: Solar wind sources; 7924 Space Weather: Forecasting (2722); 7954 Space Weather: Magnetic storms (2788).

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Citation: Howard, T. A., D. F. Webb, S. J. Tappin, D. R. Mizuno, and J. C. Johnston (2006), Tracking halo coronal mass ejections from 0–1 AU and space weather forecasting using the Solar Mass Ejection Imager (SMEI), J. Geophys. Res., 111, A04105, doi:10.1029/2005JA011349.