This technical note describes the scientific requirements of the K-coronagraph which is part of the COronal Solar Magnetism Observatory (COSMO). COSMO is a proposed facility dedicated to studying coronal and chromospheric magnetic fields and their role in driving solar activity such as coronal ma... Show moreThis technical note describes the scientific requirements of the K-coronagraph which is part of the COronal Solar Magnetism Observatory (COSMO). 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: a 1.5 m coronagraph to study coronal magnetic fields; a chromospheric and prominence magnetometer; and a K-coronagraph designed to study the formation of CMEs and the density structure of the low corona. To meet these goals, the COSMO K-coronagragh needs to acquire images of the white light corona in polarization brightness down to 1.05 solar radii (R) with a time cadence of 15 seconds to brightness levels of 10-9 B at a signal-to-noise level of one. This technical note outlines the science drivers for the K-coronagraph. The major goals are: 1) to understand the formation of coronal mass ejections (CMEs) and their interaction with surrounding coronal structures and related activity (e.g. flares, prominence eruptions and shock waves); 2) identify Earth-directed CMEs (e.g. halos) in realtime, 3) determine the density distribution of the corona over solar cycle time scales; and 4) measure the radial brightness gradients beyond 1.5 R in magnetically open regions. The COSMO K-coronagraph will replace the aging Mauna Loa Solar Observatory (MLSO) K-coronameter which has been in operation since 1980. Show less
