Electromagnetic noise from frequency driven and transient plasmas

Plasmas driven at a fixed frequency, varying frequency, or transient conditions have stochastic noise that explicitly depends upon the collision rate in the plasma. This noise from any plasma oscillating source including fluorescent lamps, discharge tubes, plasma tubes used in radar TR modules, and electron beam and arc welding can affect the electromagnetic environment. In this paper the equations are derived for oscillating plasma noise and its contribution to the electromagnetic environment. Correlation theory is used to derive the electromagnetic noise equations as a function of plasma collision frequency and driving frequency or frequencies. Correlation theory is also applied here for the electromagnetic noise from transient plasmas. Internal electromagnetic noise as well as near and far field components are derived and plotted. Applications and noise reduction techniques for oscillating plasmas are discussed. Radiation from plasma noise can cause electromagnetic interference in nearby electronic equipment. The radiated power from the plasma noise is derived in this research from charge continuity and plasma momentum equations and treating the plasma noise as a radiating dipole. The net radiated power from the stochastic plasma is calculated as a function of plasma frequency, the frequencies contained in the plasma noise, the plasma collision frequency in the plasma noise, and the dimensions of the beam and arc. With these results alone, the susceptibility of nearby electronic equipment from noise can be determined. It is seen from the derivation of the radiated power that adjustments and control of the plasma frequency and collision rate can reduce the possibilities of electromagnetic interference from plasma noise.