Influence of Non-Boltzmann Radiation around Titan Atmospheric Entry Vehicles

Hyperthermal Dynamics and Kinetics of the C(3P) + N2(X1Σg+) → CN(X2Σ+) + N(4S) Reaction

“…To model the hyperthermal chemistry in such an extreme environment, high-temperature kinetic data of the relevant reactions are essential . Atomic carbon can be formed in the boundary layer from a carbon-based thermal protection system (TPS) , and in some cases such as Titan from carbon-containing species (e.g., CH 4 ) in the atmosphere. , At high temperatures, the atomic carbon can react with N 2 , which is a major part of the atmospheres of both Earth and Titan, to form the CN radical: C ( 3 P ) + N 2 false( normalX 1 Σ g + false) → CN false( normalX 2 normalΣ + false) + N ( 4 S ) , ⁣ Δ H ° false( 0 .25em normalK false) = 47.0 kcal / mol which constitutes an important component of the kinetics. − Indeed, sensitivity analyses have identified () as a key reaction in the reaction network related to entry vehicles to Titan. − For such cases, the CN radical has also been identified as a dominant source of radiative heating due to its large transition dipole. ,, There is thus a strong desire to understand its formation chemistry and collisional excitation/quenching. So far, all kinetic data for this reaction were measured at relatively low ( T < 5000 K) temperatures, − and there is a need to provide ...…”