Characteristics of a cylindrical Langmuir probe of finite length

Journal Article · Wed May 15 04:00:00 EDT 1991 · Journal of Applied Physics; (USA)

DOI:https://doi.org/10.1063/1.347629· OSTI ID:5570103

Jaeger, E F; Berry, L A; Batchelor, D B ^[1]

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1. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8071 (US)

The current collected by a finite-length cylindrical probe is calculated numerically from a self-consistent solution to the Poisson--Vlasov system of equations. A Boltzmann distribution is assumed for the electrons, and results are compared to the standard orbital-motion-limited'' theory. When the probe is very long compared to the sheath thickness and the ratio of probe radius to electron Debye length, {ital R}{sub {ital p}}/{lambda}{sub De} {approx lt} 1, the collected current agrees with the orbital-motion theory for cylindrical probes; when the probe is very short compared to the sheath thickness and {ital R}{sub {ital p}}/{lambda}{sub De} {approx lt} 1, the collected current agrees with the orbital-motion theory for spherical probes. When the probe length is comparable to the sheath thickness, there is a critical potential above which the probe behaves as a sphere and below which it behaves as a cylinder. Ion charge density, space potential, and ion particle orbits are displayed graphically in the sheath plasma surrounding the probe tip.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5570103
• Journal Information: Journal of Applied Physics; (USA), Journal Name: Journal of Applied Physics; (USA) Vol. 69:10; ISSN 0021-8979; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700102* -- Fusion Energy-- Plasma Research-- Diagnostics
BOLTZMANN STATISTICS
BOLTZMANN-VLASOV EQUATION
CONFIGURATION
CYLINDRICAL CONFIGURATION
DESIGN
DIFFERENTIAL EQUATIONS
ELECTRIC PROBES
EQUATIONS
LANGMUIR PROBE
NUMERICAL SOLUTION
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA DIAGNOSTICS
PLASMA SHEATH
PLASMA SIMULATION
POISSON EQUATION
PROBES
SIMULATION