ABSTRACT
This chapter deals with the state-of-the-art in computer modeling of the theoretical formulations that were presented in the previous two chapters. Air plasmas are inherently complex, a situation made worse by the presence of molecular ions and electro-negative species. The air plasma consists of a high-temperature mixture of nitrogen and oxygen. With higher gas temperature, dissociation and recombination of N2 and O2 will produce more neutrals like N, 0 and NO. Further increase of the temperature prompts the ionization process to take place, producing electron population in the air. The resulting ionic species include Nt, N+, ot, 0+ and NO+, while electro-negative species are negligibly small in the amount relative to the concentration of electrons for sufficiently high temperature. Detailed mechanisms of ionization and recombination in atmospheric pressure air plasmas are yet to be fully understood. The thermal state of the air plasma may not be straightforward to describe because of the variety of populations of atoms, molecules, and diatomic molecules involved. The energy of the particles is characterized by their modes of motion, i.e. translation, vibration and rotation. The thermal state may be well described by the electron temperature and separate independent temperatures for heavy particles, since free electrons are heated rapidly by external means while heavy particles are much slower in changing their energy. A combination of computer modeling in conjunction with experiments is expected to play an essential role in filling in the gaps of our understanding and thereby lay the groundwork for our eventual mastery over air plasmas.
