9224988 Richards The Earth's hot oxygen corona may play a significant role in a number of important phenomena in the Earth's upper atmosphere. These phenomena include (1) the maintenance of the night ionosphere, (2) the helium balance (escape flux), and (3) the supply of energetic ions to the plasmasphere. Before these effects can be studied, it will be necessary to develop a numerical model of hot oxygen which will include quenching of metastable species as important new sources. It will also be necessary to develop a similar model for hot nitrogen atoms because many reactions produce energetic nitrogen atoms which may impact the hot oxygen geocorona. The new hot oxygen model will employ the 2-stream approach because it is computationally efficient and has already been successfully applied to similar problems in the atmospheres of Earth and Venus. In addition, the PI has already used the 2-stream method extensively to study the photoelectron and auroral electron problems. The work proposed here will contribute to the advancement of knowledge by enhancing our understanding of the escape of light gases from planetary atmospheres and by a better understanding of the ionosphere and plasmasphere. This is extremely important if we are to assess the likely impact of human development on the atmosphere. The work will contribute to education by providing student access to our comprehensive model of the ionosphere and thermosphere. ***
