COLLISIONAL DRIFT-LIKE INSTABILITY OF A WEAKLY IONIZED MAGNETOPLASMA WITH NO AXIAL DRIFT.
TEXAS UNIV AUSTIN ELECTRONICS RESEARCH CENTER
Pagination or Media Count:
The results of a theoretical and experimental study of the stability of inhomogeneous weakly ionized magnetoplasmas with no anial drift are reported. A linearized two-fluid hydrodynamic stability analysis yields a dispersion relation which is analyzed numerically. Oscillations with an azimuthal phase velocity approximately equal in magnitude and in the same direction as the electron diamagnetic drift are predicted to become unstable onset once the external magnetic field exceeds some critical value. This instability has been observed experimentally in a capacitively coupled radio-frequency discharge immersed in a static, uniform magnetic field. The RF discharge was utilized in order to simulate a plasma with no applied axial drift of particles. Stability criteria are displayed graphically in terms of the magnetic field strength, neutral gas pressure, and discharge tube radius. Experimental measurements are found to be in excellent agreement with the predicted values of critical magnetic field and phase velocity over a wide range of neutral gass pressures and several different discharge tube radii. The parametric dependence on pressure and magnetic field of both the theoretically predicted and experimentally measured phase velocity is similar to that expected for a drift wave. For this reason the instability is referred to as a drift instability. Author
- Plasma Physics and Magnetohydrodynamics