Proc. 42th International Instrument Symposium, p. 17−23, 1996
© Instrument Society of America

The Solar Mass Ejection Imager

B.V. Jackson, A. Buffington, P.L. Hick
Center for Astrophysics and Space Science,s University of California, La Jolla, CA, USA

G.M. Simnett
School of Physics and Space Research, Univ. of Birmingham, Edgebaston, Birmingham, UK

S.W. Kahler
Phillips Laboratory/GPSG, Hanscom AFB, MA, USA

S.L. Keil
Phillips Laboratory/GPSS, NSO/SP, Sunspot, NM, USA

D.F. Webb
ISR, Boston College, Newton Center, MA, USA


We are designing a Solar Mass Ejection Imager (SMEI) capable of observing Thomson-scattered signals from transient density features in the heliosphere from a spacecraft situated near 1 AU. The imager is designed to trace features, which include coronal mass ejections, corotating structures and shock waves, to elongations greater than 90° from the Sun. An imager at Earth could allow up to three days warning of the arrival of a mass ejection from the Sun. The instrument can be regarded as a progeny of the heliospheric imaging capability shown possible by the zodiacal light photometers of the HELIOS spacecraft. The instrument we are designing must utilize one of the most advanced baffle systems yet devised to eliminate sunlight from its wide field of view. In addition, the instrument must couple the wide field of view to a CCD camera so that the small percentage variations of the Thomson-scattered signals can be detected relative to a much brighter zodiacal light and stellar background.