Plasmadiagnostik einer Azetylen-Sauerstoff-Flamme mit Mikrowellen und Magnetfeld

Abstract

In order to determine the electron-molecule collision frequency in an acetylene-oxygen flame (burning within aX-band wave-guide) the decrease of microwave attenuation caused by an increasing magnetic field is being measured. It is shown that this decrease is equivalent to the wellknown high pass character of a plasma. The small attenuation is enlarged by using a Perot-Fabry type waveguide resonator. Nothing has to be known about its properties, since relative attenuation data are used for evaluation only. For the same reason no knowledge of electron concentration is necessary. The collision frequency value is exact within 4%, which is sufficient for excluding Coulomb collision interaction. The comparison with data in the literature is satisfying only, if the collision model of an electron induced dipol is accepted. With this and a flame temperature of about 3350 °K the collision frequency amounts to 179±7 GHz.