Microwave Measurement of the Electron-Density Profile in a Mercury Plasma

Publisher Website
Google Scholar
Abstract
An experimental method is described which permits the electron‐density profile in a circular cylindrical plasma column in the absence of a magnetic field to be measured. The method involves the propagation of plasma surface waves. Two parameters which characterize the profile are determined: α, the parabolic rate of decrease of electron density from the system axis, and T, which is a measure of the plasma‐sheath thickness. For our experimental system in which the plasma is the positive column of a mercury‐vapor dc discharge we find α=0.76±0.07 and T=0.96±0.03. (The plasma‐sheath thickness is 1−T times the discharge radius.) These results are in good agreement with Parker's theoretical prediction.