The COSMO K-Coronagraph

The COronal Solar Magnetism Observatory (COSMO) is a proposed facility dedicated to studying coronal and chromospheric magnetic fields and their role in driving solar activity such as coronal mass ejections (CMEs). COSMO is comprised of 3 instruments: 1) a 1.5 m coronagraph dedicated to the study of coronal magnetic fields; 2) a chromospheric and prominence magnetometer (ChroMag); and 3) a K-coronagraph. NCAR has provided full funding for the COSMO K-coronagraph, which will be deployed to the Mauna Loa Solar Observatory (MLSO) in the summer of 2013. It will observe the polarization brightness of the white light corona from 1.05 to 3 solar radii at a nominal observing cadence of 15 seconds. The instrument is designed to provide high time resolution, high signal-to-noise observations of the very low corona in order to study the formation of CMEs and their relation to other forms of solar activity such as prominence eruptions and flares and to determine the interactions of CMEs with coronal structures. The K-coronagraph will be used to identify Earth-directed CMEs (halos) in real-time, and to determine the density distribution of the corona over times scales of minutes to years. It will replace the aging MLSO K-coronameter (Mk4 and Mk3) which has been in operation since 1980. NCAR science is supported by the National Science Foundation (NSF).