Absorption of Microwave Power by Plasmas*

Abstract

The power absorbed by the gases He, Ar, N₂, O₂, CO₂, C₄H₁₀, and Cl₂, when excited to the plasma state by microwave absorption at 900 MHz, for power inputs of several hundred watts, has been determined experimentally. The power absorbed passes through a maximum at a pressure characteristic of each gas, in a range of 1–80 Torr. The basic plasma equations have been examined in order to give a discussion of the effects of the various physical parameters when the plasma is in a near resonance state with respect to its electron concentration.