New perspective in solar coronal physics: Giant externally occulted coronagraphs using satellites in flight formation

摘要

Formation flying opens new perspectives in solar physics, and allow to conceive giant, externally occulted coronagraphs using a two-component space system with the external occulter on one spacecraft and the optical instrument on the other spacecraft at a distance of 100m. ASPIICS (Association de Satellites Pour l'lmagerie et I'Interferometrie de la Couronne Solaire) is a mission proposed to ESA in the framework of its PROBA-3 demonstration program of formation flying which is presently in phase A. ASPIICS is a single coronagraph which will perform both high spatial resolution imaging of the solar corona as well as two-dimensional spectroscopy of several emission lines from the coronal base out to 3R_☉ using an etalon Fabry-Perot interferometer. The classical design of an externally occulted coronagraph is adapted to the formation flying configuration allowing the detection of the very inner corona as close as 0.01 R_☉ from the solar limb. By tuning the position of the occulter spacecraft, it will even be possible to reach the chromosphere and the upper part of the spicules.