An Innovative Approach to a High Resolution Coronal Imager (T-07): MUSE, the Multi-Slit Solar Explorer

The Next Generation Solar Physics Mission Science Objectives Team recommended three instruments flying in space simultaneously: a spectrometer with wide temperature coverage (T-09), a high resolution coronal imager (T-07), and a photospheric and chromospheric magnetograph and spectrograph (T-01,4,5). The coronal imager was inspired by the Hi-C rocket payload, whose successful flight in 2012 gave us a new view of the corona at resolution approximately 4 times higher (linear dimension) than AIA. For example, it showed tantalizing evidence of coronal heating by braiding of field lines. LMSAL and SAO have designed a payload that goes beyond the basic requirements for T-07 by combining an imager like Hi-C with a novel multi-slit EUV spectrograph that obtains complete line profiles in three coronal temperature ranges over an extended field-of-view (FOV). This payload is MUSE, the Multi-Slit Solar Explorer, a Small Explorer mission recently selected by NASA for a Phase A study, which could lead to a launch in 2022. MUSE will provide unprecendented observations of the dynamics of the corona and transition region to illuminate the physical processes that heat the multi-million degree solar corona, accelerate the solar wind and drive solar activity (CMEs and flares). Using multi-slit coronal spectroscopy MUSE will exploit a 100x improvement in spectral raster cadence to reveal temperatures, velocities and non-thermal processes over a wide temperature range to diagnose physical processes that remain invisible to current or planned instruments. MUSE will obtain simultaneous EUV spectra and images with the highest resolution in space (1/3 arcsec) and time (1-4 s) ever achieved for the transition region and corona, along 35 slits over a FOV similar to that of IRIS, and a larger context imager FOV. The MUSE science investigation will exploit recent advances in numerical modeling and build on the success of IRIS by combining numerical modeling with a uniquely capable observatory. The MUSE consortium is led by LMSAL and includes SAO, MSU, ITA Oslo, Stanford, ARC, GSFC, MSFC and other institutions.