The characteristics of low frequency waves in the presence of × rotation of a tandem mirror plasma are investigated using the Fraunhofer diffraction method. The observed dispersion relations are in good agreement with those of drift waves including a Doppler shift due to the × rotation velocity. The effect of the radial electricfield on the drift waves is studied quantitatively by applying a bias voltage to the end plates of the tandem mirror. The fluctuation level is observed to depend on the radial electric field E_r. The fluctuation has a maximum value when E_r 0 and decreases with increasing E_r, regardless of its sign. The radial confinement time estimated from the particle balance equation decreases as the fluctuation level increases. The dependence of the fluctuation level agrees with that evaluated from the quasi-linear theory of drift wave turbulence.

Microwave reflectometric measurement is applied to diagnose vital signal of a human. The reflectometer signal is processed by a quadrature phase detector in order to obtain both phase and amplitude components of the signal. The phase component is analyzed by using fast-Fourier transform and wavelet transform to evaluate the frequency spectrum of the heartbeat and respiration. Various applications of the microwave measurement are discussed.

In the limited regions of operation of the GAMMA10 tandem mirror, a saturation or a reduction of the stored energy in the central cell is sometimes observed. By using electrostatic and magnetic probes, the low frequency (<1 MHz) fluctuations are studied in relation to plasma parameters. Dominant fluctuations are identified to be flute type and drift type modes. Magnetic fluctuations, of which frequency is much lower than the ion cyclotron frequency, are newly observed.

Progress in microwave and millimeter-wave technologies has made possible advanced diagnostics for application to various fields, including radio astronomy, alien substance detection, plasma diagnostics, airborne and space-borne imaging radars called as synthetic aperture radars, and living body measurements. Transmission, reflection, scattering, and radiation processes of electromagnetic waves are utilized as diagnostic principles. The diagnostics are classified as active and passive systems. Specifically, active radar reflectometry has become of importance in various applications due to the possibility of high localization and accessibility of the measurements as well as the non-invasive nature of the systems. In this paper, recent development and application of radar reflectometers are described. The key words are profile reflectometry, fluctuation reflectometry, imaging radar (optics imaging and synthetic aperture imaging), and radio-optics fusion technology in order to improve the spatial resolution.

An expression for density fluctuations associated with electromagnetic waves in the ion cyclotron range of frequencies is obtained from the linearized Vlasov equation. The ratio of density to magnetic field fluctuations is discussed in connection with the reflectometer measurement in GAMMA 10.

The cross-polarization scattering diagnostic system is applied to the central-cell plasma of the GAMMA 10 tandem mirror in the study of electromagnetic plasma waves in the ion cyclotron range of frequencies. An incident ordinary (extraordinary) wave is converted to an extraordinary (ordinary) wave by magnetic fluctuations. The converted wave can propagate through the cutoff layer and reach the detector. The transmitted and reflected waves are investigated at various incident frequencies. The experimental data suggest that density and magnetic fluctuations of similar levels are excited in a plasma due to the instabilities in the ion cyclotron range of frequencies.