Induction-Coupled Plasma Torch

Publisher Website
Google Scholar
Abstract
A new method of generating a stable plasma at atmospheric pressure using inductive coupling at a frequency of several Mc is described. Methods of starting and operating this plasma in argon, and mixtures of argon with helium, hydrogen, oxygen, and air are discussed. The Fowler and Milne method was used to measure the temperature profile of the plasma under various conditions of gas flow and composition, and at several power levels. Measured peak temperatures ranged from 14 000°–19 000°K. The power losses from the plasma in the form of convection, radiation, and conduction to the nozzle walls were measured under the same conditions. Total power transferred to the plasma ranged from 1.6–3.1 kw which was approximately 50% of the input power. The extent to which local thermal equilibrium prevails in the plasma is discussed; the available evidence indicates that under the operating conditions described herein, equilibrium is closely approached.