MEASUREMENT OF MAGNETIC FLUCTUATIONS OF ELECTROMAGNETIC PLASMA-WAVES BY CROSS-POLARIZATION SCATTERING

The cross-polarization scattering (CPS) technique was applied to the G AMMA 10 tandem mirror for measurements of internal magnetic fluctuatio ns associated with waves in the ion cyclotron range of frequency. The CPS is related to the mode-conversion effect consisting of a polarizat ion difference of a scattered wave with regard to an incident wave. in GAMMA 10, the incident ordinary (extraordinary) wave is transferred t o the extraordinary (ordinary) wave by magnetic field fluctuations nea r the cutoff layer of a plasma. The transferred wave penetrates throug h the cutoff layer and is detected. The frequency spectra and density and magnetic field fluctuations of the waves are evaluated from the CP S diagnostic and reflectometry. The ratio of the magnetic held to dens ity fluctuation level depends on the phase velocity of the slow Alfven wave. The CPS data are also compared with those obtained from magneti c probes. (C) 1997 American Institute of Physics.