Identifying Spectral Lines to Study Coronal Mass Ejection Evolution in the Lower Corona

Abstract

As prominences propagate away from the Sun via a coronal mass ejection (CME), they expand, accelerate, and are strongly heated. The heating is substantial enough to continuously ionize the prominence plasma, making it difficult to follow its dynamic evolution with a single extreme ultraviolet (EUV) narrow-band channel or a white light instrument. In this work, we identify useful spectral lines that can be utilized to study the prominence during the early stages of propagation. We generate nonequilibrium ion fractions from a previously studied multi-thermal component CME using the Michigan Ionization Code to compute synthetic intensities along the CME path. We test several emission lines produced by the multi-thermal evolution of the CME that span the EUV to the visible and infrared wavelength range, 100-14400 Å, and equilibrium formation temperatures between log(T e)=4.3-6.7. We assess the visibility and diagnostic potential up to 2 solar radii of many lines in a wavelength range encompassing the EUV to the near-infrared, including those observed by many existing and past instruments, as well as upcoming observatories, such as the Daniel K. Inouye Solar Telescope, Upgraded Coronal Multi-channel Polarimeter, and Solar Orbiter/Spectral Imaging of the Coronal Environment.