No abstract

Aust. J. Phys., 1978, 31, 477-87 This paper reports on the use of observations of magnetoacoustic oscillations to determine the radial particle density and temperature profiles in a hydrogen plasma. The observations comprise measurements, at a number of frequencies, of the radial variations of the oscillation amplitude and of the total flux in the plasma. The analysis allows the determination of radial profiles of the ion and atom number densities.

This paper reports on theoretical and experimental refinements in the use of forced radial magneto-acoustic oscillations of a magnetized plasma as a diagnostic technique. The theory of such oscillations is extended to include radial variations in electron number density, neutral atom density and plasma temperature. In experiments carried out in an argon afterglow plasma, observations of the radial variation of the oscillation amplitude, and of the total flux in the plasma, are combined with theory to yield radial density and temperature profiles. These profiles are in good agreement with independent measurements made using laser interferometry and spectroscopic techniques.

Numerical calculations of linear magnetoacoustic resonant phenomena in a plasma containing two species of ions have been made for a cylindrical plasma with a model which includes the effects of collisional damping and radial non-uniformities in temperature and number density. At sufficiently high temperatures two frequencies are predicted at which magnetoacoustic resonances for the first radial mode will occur. These are expected from considerations of the effects of the ion-ion hybrid resonance.