Numerical model of operation of the Langmuir probe under intermediate pressure

Conference · Tue Dec 31 04:00:00 EST 1996

OSTI ID:419678

Dudin, S V ^[1]

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1. Kharkov State Univ. (Ukraine)

The technique of a Langmuir probe is known reasonably well. However, despite plenty of work devoted to calculation of currents on the probe inserted into plasma, a theory does not at present exist which would allow calculation of plasma parameters at any size of the probe and pressure of the working gas. While the theory of a probe in absence of collisions is developed rather in detail by Bernstain and Rabinovich, Laframboise, Allen, and others, there is no rigorous theory which describes a probe under high pressure of a gas. As for intermediate pressure, the theories are absent. Solution of the problem is in this case considerably complicated because of non-local dependence of density of charged particles on potential or electric field strength that means unusability of hydrodynamic approach and necessity of application of the kinetic theory. To fill in this gap the author has developed a numerical model of ion kinetics in a near-boundary layer of a Langmuir probe, inserted into a weakly-ionized gas-discharge plasma, in a range of intermediate pressure of a neutral gas as well as at any ratio between thickness of the layer of space charge and radius of the probe. On the base of results of modeling, practical technique of processing of pore characteristics at intermediate pressure is developed: (i) a technique of calculation of density of ions; (2) a technique of division of a probe current on electron and ion part.

• OSTI ID: 419678
• Report Number(s): CONF-960634--
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
LANGMUIR PROBE
MATHEMATICAL MODELS
NUMERICAL SOLUTION
OPERATION
PLASMA DIAGNOSTICS
PRESSURE DEPENDENCE