Proc. SPIE 2804, 78−89, 1996
Missions to the Sun
D. Rust (ed.)
© SPIE − The International Society for Optical Engineering

Solar Mass Ejection Imager (SMEI)

Stephen L. Keil, Richard C. Altrock, and Stephen Kahler
Air Force Phillips Lab. (USA)

Bernard V. Jackson, Andrew Buffington, and Pierre P. Hick
Univ. of California/San Diego (USA)

George M. Simnett and Christopher J. Eyles
Univ. of Birmingham (United Kingdom)

David F. Webb
Boston College, USA

Peter Anderson
Boston Univ., USA


The Solar Mass Ejection Imager (SMEI) experiment is designed to detect and measure transient plasma features in the heliosphere, including coronal mass ejections, shock waves, and structures such as streamers which corotate with the Sun. SMEI will provide measurements of the propagation of solar plasma clouds and high-speed streams which can be used to forecast their arrival at Earth from one to three days in advance. The white light photometers on the HELIOS spacecraft demonstrated that visible sunlight scattered from the free electrons of solar ejecta can be sensed in interplanetary space with an electronic camera baffled to remove stray background light. SMEI promises a hundred-fold improvement over the HELIOS data, making possible quantitative studies of mass ejections. SMEI measurements will help predict the rate of energy transfer into the Earth's magnetospheric system. By combining SMEI data with solar, interplanetary and terrestrial data from other space and ground-based instruments, it will be possible to establish quantitative relationships between solar drivers and terrestrial effects. SMEI consists of three cameras, each imaging a 60 degree(s) X 3 degree(s) field of view for a total image size of 180 degree(s) X 3 degree(s). As the satellite orbits the earth, repeated images are used to build up a view of the entire heliosphere.