| The effect of nonthermal atoms is investigated in planetary, satellite, and cometary atmospheres. In the Earth's lower thermosphere, it is demonstrated that nonthermal N(4S) and O(3P) atoms increase the peak NO density, bringing closer model and observational (108 cm-3) densities. However, they are insufficient to remove the total NO deficit and only result in a peak NO density of approximately 3 x 107 cm-3 at 105 km. The loss of nonthermal N(4S) atoms from Titan and Triton are found to be 9 x 1024 and 1.5 x 1024 N atoms s-1, respectively. We find that the observational estimates of Strobel et al. [1992] are consistent with our modeling of escape from Titan.;The loss of O atoms from Mars by nonthermal processes is a vital part of understanding the H2O and CO2 budgets in respect to how the Martian atmosphere has evolved. Anderson and Hord [1971] inferred the H escape flux to be approximately 1.8 x 108 cm -2 s-1 from Mariner 6 and 7 ultraviolet data. McElroy et al. [1977] initially calculated an 0 atom escape rate that was approximately half the H escape rate. However, with more sophisticated modeling this result was shown to be an order of magnitude too large [Lammer and Bauer, 1991; Fox, 1993; Luhmann, 1997]. In this work, we demonstrate that the O escape rate due to dissociative recombination of O2 + can be in stoichiometric balance with H escape over a solar cycle.;Observations of comet Hale-Bopp reveal a third type of tail consisting of neutral sodium atoms. Using a point source of atomic sodium to model the observed tail, the sodium production is found to be 3.5 x 10 25 atoms s-1. This result suggests that the source of the sodium is either from the nucleus or inner coma. The production rates of water and carbon monoxide near perihelion are found to be 1031 s-1 and 2.7 x 1030 s-1 , respectively. The abundance of observed Na in the tail is inconsistent with cosmic abundances, suggesting that the majority of the sodium is trapped in the comet nucleus or dust grains. |
