Measurements of the impedance of a magneto-acoustic wave-launching antenna

Magnetoacoustic waves were generated in an argon plasma by passing an RF current through a solenoid antenna surrounding the plasma column. The complex impedance of the antenna was measured as a funcion of wave frequency in order to investigate the column geometric resonances and to obtain estimates of ion density and electron temperature. Although this technique yielded reliable estimates of the ion number density, the wave &litudes near resonance were found to be anomalously low and reliable temperature measurements could not be obtained.