Non-Equilibrium Radiation Transport
To calculate the radiative properties of a gas it is necessary that the occupation numbers of the various atomic states of the gas particles be known. If the gas is in LTE, the occupation numbers can be expressed in terms of the local temperature and atomic parameters by using standard statistical mechanics. The only parameters required are the energies and statistical weights of the atomic states. When LTE conditions do not prevail, determination of the occupation numbers becomes much more complicated. In general, the occupation numbers depend on the state of the radiation field, so the equations governing the atomic configuration of the gas and the transport of radiation must be solved simultaneously.
KeywordsTransport Equation Collision Frequency Occupation Number Scattered Photon Radiation Rate
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