Non-Equilibrium Gas Velocity Distributions and a Model of the Atomic Oxygen Geocorona.

It is believed that velocity distributions which are markedly different from Maxwellian are important in determining reaction rate kinetics in the upper atmosphere. A numerical technique for accurately simulating the collision integral in the non-linear Boltzmann Equation is described. This technique is "tested" on several problems, previously solved by other methods, to measure its accuracy in determining steady-state and time-dependent velocity distribution functions. Finally, it is used in conjunction with a Monte Carlo method that simulates transport, to model the terrestrial atomic oxygen corona.