Accession Number : AD0283839

Title :   PLASMA SHEATH FORMATION BY RF FIELDS,

Corporate Author : STANFORD UNIV CALIF MICROWAVE LAB

Personal Author(s) : Butler ,H. S. ; Kino,G. S.

Report Date : JUL 1962

Pagination or Media Count : 31

Abstract : It has been observed that the application of a radio-frequency voltage (10 kc/s - 50 Mc/s) to any one of several electrode configurations around to outside of a plasma discharge tube results in a constriction of the luminous portion of the plasma away from the inner walls of the glass tube. This investigation has established that the phenomenon is the result of an interaction between the externally applied rf voltage and the plasma which leads to the formation of a dc positive ion sheath. The physical mechanism by which the interaction occurs is basically one of rectification. The current flowing from the plasma can be represented as the resultant of two voltage-dependent current sources, one relating to the dc probe characteristic of the plasma, the other to the physical movement of a body of electrons toward and away from the wall. There must be no average net current flowing from the plasma to the wall - an insulator. The interaction is described in terms of a differential equation whose solution is shown to fit qualitatively all the general characteristics of the phenomenon with regard to its dependence on arc current. The differential equation in its most general form was solved numerically and the solution shown to fit experimental observations quantitatively for both square and sine wave inputs. (Author)

Descriptors :   *PLASMAS(PHYSICS), *RADIOFREQUENCY POWER, ALTERNATING CURRENT, DENSITY, DIFFERENTIAL EQUATIONS, DIRECT CURRENT, DISCHARGE TUBES, ELECTRIC DISCHARGES, ELECTRODES, FREQUENCY, IONS, PLASMA SHEATHS

Distribution Statement : APPROVED FOR PUBLIC RELEASE