Исследование резонансных характеристик СВЧ плазмотрона на волне TE₁₁ (H₁₁) для плазмохимического осаждения на кварцевые стержни (трубы, заготовки) оптических структур специальных волоконных световодов на основе кварцевого стекла, легированного фтором и азотом, в неизотермической плазме резонансного локального СВЧ-разряда пониженного давления

In this paper we presented some results of research made on a resonator microwave plasmatron, working on H₁₁₁ mode at low oxygen pressure, to investigate its resonance features. In the beginning the setting into resonance of non-loaded resonator algorithm is described (so-called, “cold measurements”). It is carried out using adjusting quartz glass rods, placed into a resonant cavity through special holes, located equidistantly in azimuthal direction. Such setting is done at different frequencies; it sets relation between space location of rods and resonance frequency of the plasmatron at low power level. Next,an ignition of plasma is made through input to plasmatron of high microwave power from a generator having a constant frequency. In this case resonator is loaded to low-pressure, non-equilibrium UHF-discharge plasma (so-called, “hot measurements”). Monitoring results of rejected power, we adjusted resonator by quartz rods such as to achieve its minimum, which corresponds to maximum of absorbed power. We show three curves of relation between a power, absorbed in plasma, and configuration of setting rods, uniquely related in cold measurements with some resonance frequency. These frequency values are abscissas of curves points. Three curves are showed for three different values of pressure. This results confirm the assumption that plasma-loaded resonator plasmatron saves a good expressed resonance character, but with significantly increased curve’s width. Therefore, during the technological process continuous monitoring and stabilization of the resonant mode is required.