COronal Magnetism and Plasma ASsembled Scopes(COMPASS)

Finding out and identifying mechanisms responsible for coronal eruptions, coronal heating and solar wind acceleration form the cores in solar physics research, and such mechanisms are crucial for us to establish efficient models for predicting the catastrophic space weather and even for sun-like stars. As one important element of the Ground-based Advanced Solar Observatory (ASO-G), the proposed COronal Magnetism and Plasma ASsembled Scopes (COMPASS) consist of three coronagraphs of different sizes. They are respectively the coronal magnetism probing refractive Lyot coronagraph with an aperture of 1.26 m, called COMPT, improved from American COSMO-LC, a two-dimensional spectroscopic diagnosis coronagraph with an aperture of 0.30 m, named TSDC, and a small Lyot coronagraph with an aperture of 0.09 m attached to COMPT for monitoring. Observations of COMPT focus on the accurate measurement of vector magnetic fields and other physical parameters in a height range of 0.05–0.65 solar radius above solar limb by two observing modes, the integral field Stokes spectroscopy (IFS) realized by a pair of integral field units and corresponding spectrometers as well as two-dimensional imaging Stokes spectroscopy (TDIS) by dual tunable Lyot filters, and the reduced polarimetric optical switching is applied for high precision polarimetry, while observations from TSDC will provide information on the necessary physical parameters of coronal plasma in a field of view with height range from 0.10 to 1.5 solar radii, with help of Fabry-Perot interferometer to carry out the imaging spectroscopy as well as white light polarization imaging. These three coronagraphs form a complementary set. The scientific and observational goals are stated and then the preliminary optical, mechanical and electronic control designs of these coronagraphs are described. Finally the innovative ideas to serve the goals are outlined.