Input impedance of a short dipole antenna in a warm anisotropic plasma, 2, Experiment


  • D. T. Nakatani,

  • H. H. Kuehl


The measured input impedance of a short, cylindrical dipole immersed in a pulsed, RF discharge, anisotropic, argon plasma is presented. The experimental results show that the input impedance undergoes a pronounced change when the antenna frequency passes through the harmonics of the electron cyclotron frequency, which is in agreement with the predictions of kinetic theory. In general, the correlations between experimental and theoretical results are judged as fair to very good over a wide range of plasma parameters. Effects of the plasma sheath are found to be important and a sheath correction term based on a simple sheath model is included for correlating experimental and theoretical results. Using a curve-fitting technique, a sheath thickness of 3λD was determined. Impedance measurements at dipole frequencies above the harmonics showed anomalous results which are explained by kinetic theory.