Measurement of the Complex Conductivity of an Ionized Gas at Microwave Frequencies

Author: Adler, Fred Peter

Year: 1950

Degree: Dissertation (Ph.D.)

Advisors: Pickering, William Hayward; Mackeown, Samuel Stuart

Committee Members: Pickering, William Hayward; Lindvall, Frederick C.; McCann, Gilbert Donald; Neher, Henry Victor; Ramo, Simon; Smythe, William Ralph; Sorensen, Royal Wasson

Option: Electrical Engineering; Physics

DOI: 10.7907/705A-3B21

Abstract

The positive column of a glow discharge is placed along the axis of a cylindrical cavity excited in the TM010 mode. The transmission of 3 cm waves through the cavity and the shift in resonant frequency are observed as a function of discharge current. It is shown that from these measurements values of the complex conductivity of the electron gas can be calculated. Curves of the measured conductivity components as functions of pressure and current are given. From theoretical expressions for the conductivity values of electron density are calculated. Langmuir probe studies are carried out and adequate agreement is found. Finally, mean free path and mean free time between collisions are calculated from the conductivity values and hence the variation of collision cross-section with temperature is found.

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