Further research of the collisional instability. An extensive study of growth and a notable influence of the boundaries

Abstract

AbstractIn a cylindrical geometry, a low-pressure magnetized argon plasma is lit, using the rf upper hybrid resonance. As a radial dc electric field is formed, a perpendicular drift velocity is obtained on the charged particles and a collisional instability is raised. The description, study and identification of that wave were given in the last published work from NCSR ‘Demokritos’, both experimentally and theoretically. Since then, the research has been continued and significant results have been obtained concerning the fields of plasma parameters, wave further understanding, growth research and boundaries' strong influence. The aim of the present paper is to inform that the rising instability has many of the characteristics of drift instabilities that are caused by the density gradient, as well as the ability of it's frequency to overcome the ion gyro-frequency. In addition, it gives an answer to the well-known problem of the need to consider a small component of the wave vector in the parallel direction, in order the wave to rise through the electron-neutral collisions' proceedings; a strong influence of cavity length on wave amplitude has been observed and measured.