Accession Number : AD0434842

Title :   THE LANGMUIR PROBE IN A COLLISIONLESS PLASMA,

Corporate Author : PRINCETON UNIV N J GAS DYNAMICS LAB

Personal Author(s) : Lam,S. H.

Report Date : MAR 1964

Pagination or Media Count : 69

Abstract : This paper presents an asymptotic analysis of the Langmuir probe problem in a quiescent, collisionless plasma in the limit of large body dimension to Debye length ratio. The structures of the electric potential distribution about spheres and cylinders are analyzed and discussed in detail. It is shown that when the probe potential is smaller than approximately 1/2-KT, where T is the undisturbed temperature of the repelled particles, there exists no sheath adjacent to the solid surface. At large body potentials, for which a sheath is present, the electric potential distribution is given in terms of several universal functions. Master current-voltage characteristic diagrams are given which exhibit clearly the effects of all the pertinent parameters in the problem. An explicit trapped-ion criterion is presented. The general problem with an arbitrary body dimension to Debye-length ratio is qualitatively discussed. (Author)

Descriptors :   (*PROBES (ELECTROMAGNETIC), PLASMA MEDIUM), IONIZATION POTENTIALS, PARTICLE TRAJECTORIES, STATISTICAL FUNCTIONS, SPECIAL FUNCTIONS (MATHEMATICAL), SPHERES, CYLINDRICAL BODIES, PLASMA SHEATHS, PARTICLES, STATISTICAL MECHANICS, TABLES(DATA), NUMERICAL ANALYSIS

Distribution Statement : APPROVED FOR PUBLIC RELEASE