Computational investigation on the disturbed thermal plasma for improving the reliability of electrostatic diagnosis

For measuring the current-voltage (I-V) characteristic curve with respect to flowing plasmas, a Langmuir probe, a conducting object, should be inserted to the region directly, and the interaction between the probe and the flowing plasma is not avoidable. This interaction can cause the serious problem for plasma diagnostics due to aerodynamic and thermal disturbances generated by inserting the metallic probe. In spite of the problem related to the disturbances, the conventional probe theory assumes a connection between the measured probe currents and parameters of the undisturbed plasma. Unfortunately, the simplicity of the operating scheme is not reflected by the appropriate theories for the disturbed plasma. Also, the disturbed region should be affected by the size of the inserted probe, and this calls for a small probing object not to perturb the global state of the plasma. The main purpose of this paper is to know the disturbances of the original temperature and velocity fields, which are called as thermal and aerodynamic disturbances, of the entire free-burning arc disturbed by the inserted metallic probe with the turbulent model.