Title:
A kinetic model of the formation of the hot oxygen geocorona. 1: Quiet geomagnetic conditions
Authors:
Shematovich, V. I.; Bisikalo, D. V.; Gerard, J. C.
Affiliation:
AAInstitute of Astronomy of the Academy of Sciences, Moscow, Russia ABInstitute of Astronomy of the Academy of Sciences, Moscow, Russia ACUniv. de Liege, Belgium
Journal:
Journal of Geophysical Research (ISSN 0148-0227), vol. 99, no. A12, p. 23,217-23,228
Publication Date:
12/1994
Category:
Geophysics
Origin:
STI
NASA/STI Keywords:
BOUNDARY LAYER TRANSITION, DYNAMIC MODELS, ENERGY DISTRIBUTION, EQUATORIAL ATMOSPHERE, EXOSPHERE, GEOMAGNETISM, OXYGEN, PARTICLE COLLISIONS, PHOTODISSOCIATION, ATMOSPHERIC COMPOSITION, BOLTZMANN TRANSPORT EQUATION, GEOCORONAL EMISSIONS, MARKOV PROCESSES, MONTE CARLO METHOD, THERMOSPHERE
Bibliographic Code:
1994JGR....9923217S

Abstract

A model of the hot oxygen geocorona in the transition region near the exobase is described. It is based on a Monte Carlo solution of the nonlinear Boltzmann equation for hot oxygen atoms produced by chemical processes usually considered as a source of hot oxygen (photodissociation of O2 and dissociative recombination of O2(+) and NO(+) ions). The evolution of the system is described stochastically as a series of random Markovian processes. The energy distribution function of the thermal and non-thermal O(3P) atoms and of the nonthermal O(1D) atoms is calculated from the thermospheric collision-dominated region to the exosphere where the gas flow is virtually collisionless. The model is applied to equatorial latitudes for conditions of low solar and geomagnetic activity. Numerical simulations show that the distribution function of thermal oxygen is increasingly perturbed by collisions with the hot oxygen population at high altitudes and departs significantly from a Maxwellian distribution at all altitudues. The number density and temperature of the nonthermal oxygen atoms are derived from their microscopic distribution function and found tobe in qualitative agreement with previous theoretical and experimental estimates.