Development of Atmospheric Pressure Helium Collisional-Radiative Model by Including Atomic Collisions

A helium collisional-radiative (CR) model is expanded for use in the atmospheric pressure range. By including the atomic collision processes (atomic collision excitation and deexcitation, atomic collision ionization and atomic three-body recombination) in the low-pressure CR model, this new model is capable of diagnosing atmospheric-pressure helium plasma. The population density of all the excited states can be calculated by inputting the electron density, electron temperature, gas temperature, population density of ground state helium atoms, pressure, and geometrical parameters. Additionally, the electron temperature and density of atmospheric-pressure helium plasma can be estimated by inverting the previously described CR model and OES measurement.