A study of ion emissions in MAVEN/IUVS data

The Imaging Ultraviolet Spectrograph (IUVS) instrument on the Mars Atmosphere and Volatile EvolutionN (MAVEN) mission is designed to measure radiances of several of the most abundant species present in Mars' atmosphere. Many spectral features are associated with ions; one of the most prominent spectral features in the mid-ultraviolet region is the CO[SUB]2[/SUB][SUP]+[/SUP] Ultraviolet Doublet (UVD) at 289 nm. However this emission, and many others, results from several radiative processes, some of which originate from the ionization process and is therefore not diagnostic of the ion densities. Several other emissions are diagnostic of ion densities, especially at high altitudes, and therefore lend themselves to density retrievals based on inclusion of all radiative processes. The most promising of these is the Fox-Duffendack-Barker (FDB) (3,0) band at 314 nm, near the long-wavelength limit of the IUVS instrument. We report on a new process for performing density retrievals of CO[SUB]2[/SUB][SUP]+[/SUP] with particular attention to the credibility of high-altitude signal in the FDB bands as well as the associated uncertainties. We also investigate the feasibility of C[SUP]+[/SUP] and other ion density retrievals.