Macroscopic Instability of the Positive Column in a Magnetic Field

Publisher Website
Google Scholar
Abstract
The positive column of a glow discharge has previously been shown to become unstable when immersed in a longitudinal magnetic field of the order of 1 kgauss, the instability transforming the azimuthally symmetric column into a constricted rotating helical stage. The measurements have been extended, with emphasis on the properties and growth of the instability, to permit a quantitative comparison between experiment and the theory of Kadomtsev and Nedospasov. The properties of the helical state have been measured in H2, D2, He, and Ne as functions of gas pressure and tube radius. The dependence of the critical magnetic field, and the frequency and wavelength of the oscillation on the kind of gas, pressure, and the tube radius are in fairly good agreement with the predictions made by the perturbation theory of Kadomtsev and Nedospasov. It is interesting that the onset of the instability is also fairly well predicted by the simple sheath-instability theory of Hoh, but the agreement is not as good as in the previous case, nor is the nature or appearance of the instability specified.

This publication has 19 references indexed in Scilit: