Radio-frequency transmission spectroscopy in the ion-cyclotron frequency range in the minimum-B anchor of the GAMMA 10 tandem mirror

다국어 초록 (Multilingual Abstract)

A wide-band radio-frequency (RF) probe system was newly constructed for the active diagnostic
of the eigenmode formations in the ion-cyclotron range of frequencies in the GAMMA 10 tandem
mirror. A bar-type antenna was installed in the peripheral region in the minimum-B anchor cell.
A low-power RF pulse with the frequency sweep from 8 to 20 MHz is applied to the antenna. The
waves excited in the plasma are detected with a magnetic probe. The excitation of eigenmodes
is described by using the antenna-plasma-probe transfer function. The transfer function can be
obtained from the antenna current signal and the magnetic probe signal. When the real and the
imaginary part of the transfer function are plotted in the complex plane, the resultant curves are
approximately circles, indicating an eigenmode formation. It is found that the several fast wave
eigenmodes can be excited in the present experimental condition.