Analysis of Nonequilibrium CN Radiation Encountered During Titan Atmospheric Entry

摘要

The focus of this paper is to analyze the Titan reaction scheme and determine the mechanisms that control the formation and decay of the radiation emitted by the cyanogen molecule (CN) during entry into Titan's atmosphere. Through a parametric study of important reactions combined with an investigation into reaction pathways, it has been concluded that the coupling between the dissociation of N_2 and the formation of the CN (through the reaction N, + C ←→ CN + N) controls the radiation decay rate. The reason for the super equilibrium concentrations (approximately 50% higher than equilibrium) was identified to be a result of the N_2 + C ←→CN + N reaction continuing to overproduce the CN after nominal equilibrium values were reached. This is due to the slow buildup of N to drive the reverse reaction. The absolute level of emitted radiation has been shown to be controlled by the lifetime of the CN(B) state and the excitation of CN(X) to CN(B) by heavy particle impact Thus, it is the conclusion of this paper that CN radiation is primarily controlled by N_2 dissociation.