Speaker
Description
An important goal of the Solar-C EUVST spectrometer is to make seamless observations from the chromosphere to the corona. Within its spectral range are potentially hundreds of chromospheric lines from highly excited, Rydberg levels in neutrals. Since the majority of the lines form in LTE the modelling is greatly simplified, and yet their diagnostic potential has largely been untapped in the literature. Using recent atomic data for these lines in carbon, we have carried out radiative transfer calculations with the Lightweaver code to determine the conditions under which the lines form and their response to changes in atmospheric parameters. We found that the lines form low in the chromosphere, thus widening the expected range that EUVST will cover. The work also identified a number of neutral carbon lines that were either unknown or previously misidentified in quiet Sun spectra. The accuracy of the theoretical energies is such that these lines are useful references for wavelength calibration and Doppler measurements.
