Cor-I: A coronal white-light imager for a solar probe

Solar and heliospheric observations acquired over several decades, have shown that the corona is a highly structured medium. There is no doubt that these structures reflect the response of the coronal plasma confined by the highly inhomogeneous magnetic field - to different forms of energy input. While in-situ plasma measurements have provided the characteristic properties of both fast and slow solar winds, they have fallen short in connecting them to the source regions of the wind. A near-Sun flyby mission offers an unprecedented opportunity to explore the solar wind at distances much closer to the Sun than ever achieved before. However, it is essential that in-situ measurements be coordinated with simultaneous <(imaging)under bar> of the structures encountered in the corona. We present the concept and design of a white-light imager called Cor-I, as a key instrument for a near-Sun flyby mission which makes it possible to distinguish spatial structures from temporal changes in the plasma parameters. With the inference of the electron density from the Thomson scattered emission, white-light measurements are also a very powerful tool for quantitative studies of the acceleration region of the solar wind. In addition, the proposed instrument carries the potential for discovery of transient events and waves in these parts of the acceleration region of fast and slow solar winds that are inaccessible to in-situ plasma instruments. (C) 1998 COSPAR. Published by Elsevier Science Ltd.