The chemistry of protonated species in the martian ionosphere

Photochemical determination of O densities in the Martian thermosphere: Effect of a revised rate coefficient

“…This has been predicted by many models for the last 45 years, which are too numerous to cite here [e.g., McElroy, 1972;McElroy et al, 1977;Fox and Dalgarno, 1979;Krasnopolsky, 2002;Matta et al, 2013;Bougher et al, 2014;, and confirmed by measurements made by the Neutral Gas and Ion Mass Spectrometer (NGIMS) instrument [e.g., Mahaffy et al, 2015] on the Mars Atmosphere and Volatiles EvolutioN (MAVEN) spacecraft [e.g., Jakosky et al, 2015]. This has been predicted by many models for the last 45 years, which are too numerous to cite here [e.g., McElroy, 1972;McElroy et al, 1977;Fox and Dalgarno, 1979;Krasnopolsky, 2002;Matta et al, 2013;Bougher et al, 2014;, and confirmed by measurements made by the Neutral Gas and Ion Mass Spectrometer (NGIMS) instrument [e.g., Mahaffy et al, 2015] on the Mars Atmosphere and Volatiles EvolutioN (MAVEN) spacecraft [e.g., Jakosky et al, 2015].…”

“…This method or some variant of it has been used often to obtain the O densities or mixing ratios from the chemistry of the major ions, O + 2 , CO + 2 , and O + , which were measured by the Viking retarding potential analyzer (RPA) [Hanson et al, 1977], in concert with the CO 2 density profiles measured by the Viking 1 neutral mass spectrometer [e.g., Nier and McElroy, 1977]. Fox and Dalgarno [1979] derived an O mixing ratio of 1.4% at 120 km, rising to 3% at 130 km, based on photochemical equilibrium calculations of CO + 2 . Photochemical equilibrium calculations of the ionosphere of Mars have been carried out by, for example, Hanson et al [1977], who derived an O mixing ratio of 1.5% at 130 km from the Viking measurements.…”

Planetary space weather: scientific aspects and future perspectives

“…Our current knowledge of the upper Martian atmosphere has been summarized very recently in Fox (2015). Fundamental experimental data were derived from the observations of airglows by the Spectroscopy for Investigation of Characteristics of the Atmosphere of Mars (SPICAM) instrument on-board Mars Express: while NO is useful to constrain dynamics around the 100 km level (Gagné et al 2013), CO and CO 2 + UV emissions allow the direct monitoring of the efficiency of ionization processes .…”

Radiation Effects on Airless Bodies in Space: Radiolysis, Sputtering, and Sintering in Regoliths

“…The ejected ions can be directly analyzed using an IMS, thereby allowing detection of reactive metal ions and molecules which would otherwise stick to the instrument walls before they could be ionized and measured. It has long been suggested that secondary ions could be used to determine the composition of airless bodies in space [Johnson and Baragiola, 1991;Dukes and Baragiola, 2015;Johnson and Sittler, 1990], and recent spacecraft have shown promise by obtaining rough elemental analyses of both atmospheres [Waite et al, 2004;Fox, 2015] and surfaces [Mahaffy et al, 2014;Balsiger et al, 2007] using this technique. This work combines laboratory data and simulations to estimate the material ejection rates and the resulting neutral and ion fluxes as a function of altitude above a small body on which sputtering is occurring.…”

“…It has long been suggested that secondary ions could be used to determine the composition of airless bodies in space [Johnson and Sittler, 1990;Johnson and Baragiola, 1991;Dukes and Baragiola, 2015]. Recent spacecraft have shown the promise of obtaining detailed elemental analysis of ions from both atmospheres such as those of Titan [Waite et al, 2004] and Mars [Fox, 2015] and from airless surfaces such as the Moon [Mahaffy et al, 2014] and comets [Balsiger et al, 2007].…”