Temperature anisotropy measurement using diamagnetic loop array

The anisotropy of the ion distribution function in the velocity space is observed in the ion cyclotron range of frequency heating experiments on the tandem mirror GAMMA 10. The anisotropy, defined as T perpendicular / T parallel (ratio of ion temperatures perpendicular and parallel to the magnetic field line), is evaluated quantitatively using three diamagnetic loops aligned in the direction of the magnetic field line. Depending on the anisotropy and the plasma pressure, fluctuations below the ion cyclotron frequency are excited. In terms of the quantitative estimation of the anisotropy, it is established clear that the parameter region in which the fluctuations are observed agrees well with a theoretically predicted region of the convectively unstable Alfven ion cyclotron mode. (author)