Authors: J. Luhmann et al and the STEREO Science Teams
Affiliation: Space Sciences Laboratory, University of California, Berkeley
STEREO (Solar Terrestrial Observatory), a Solar Terrestrial Probe mission, is due to launch in February 2006. The primary goal of the mission is to decipher the 3-dimensional attributes of coronal mass ejections and their associated interplanetary consequences. Toward this end, STEREO's twin-spacecraft carry white light coronagraphs and heliospheric imagers, EUV solar imagers, radio and plasma waves antennas, and in-situ experiments for measuring the plasmas, magnetic fields, and solar energetic particles at 1 AU. The solar imaging, radio/plasma waves, and in-situ investigations, SECCHI, SWAVES, IMPACT and PLASTIC, respectively, are supported by international teams of scientists including modelers. Following four geocentric transfer orbits, the STEREO spacecraft will use lunar gravitational assists to attain heliocentric orbits nearly coincident with Earth's orbit. The Ahead spacecraft moves ahead of the Earth and the Behind spacecraft trails Earth, each separating from Earth's location at ~22 deg/year. With this increasing baseline for the two views, STEREO imagers will be able to determine whether CMEs are more bubble-like or loop-like and whether they originate from active region arcades or in the helmet streamer arcade or both. The relationship of the 3D CME to its coronal shock and associated flare will be obtained with simultaneous radio remote sensing and prompt solar energetic particle probes, while the magnetic topology and plasma domains of the interplanetary CME or ICME are traced to the 3D topology and origins of the coronal ejecta and surrounding solar wind. The interpretation of STEREO data will be greatly complemented by L1 measurements from SOHO, ACE and WIND spacecraft. At its launch at the beginning of the new solar cycle, when events should be relatively isolated and simple, STEREO will subject the increasingly sophisticated numerical models of CMEs and their propagation to unprecedented observational validation. Space Weather forecasters will evaluate a new perspective for forecasting magnetic storms from its oblique images of Earthward-directed CMEs. In short, the science and related applications of STEREO data will provide an exciting new perspective on space weather consistent with LWS interests and objectives.