Measurement of the charging of individual dust grains in a plasma

Journal Article · Fri Apr 01 00:00:00 EST 1994 · IEEE Transactions on Plasma Science (Institute of Electrical and Electronics Engineers); (United States)

DOI:https://doi.org/10.1109/27.279010· OSTI ID:7112636

Walch, B ^[1]; Horanyi, M ^[2]; Robertson, S ^[3]

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1. Univ. of Northern Colorado, Greeley, CO (United States). Dept. of Physics
2. Univ. of Colorado, Boulder, CO (United States). Lab. for Atmospheric and Space Physics
3. Univ. of Colorado, Boulder, CO (United States). Dept. of Astrophysical, Planetary, and Atmospheric Sciences

Many natural plasmas are contaminated with dust particles. The dynamics of cometary, magnetospheric, and interstellar plasmas is determined by the electromagnetic forces on the plasma, the gravitational and electromagnetic forces on embedded dust grains, and the coupling of the grains and the plasma. Of primary importance is the charge on the grains which has been determined by using the theory of the Langmuir probe and by simulation. A recently constructed experiment is described for investigating the charging of dust grains in a plasma. The apparatus is a double plasma device into which single dust grains are dropped from the top. The dust charge is detected and measured by a sensitive electrometer attached to a Faraday cup on the bottom. Experiments with electrons from the emissive filaments but without plasma indicate that the grains charge to approximately the filament potential for filament bias voltages smaller in absolute value than [minus]70 V. The charge is of order 10[sup 6] electrons for SiC grains 30--150 [mu]m in diameter. At higher bias voltage the charge is reduced due to secondary emission. The charge on grains increases with grain size and is nearly independent of the filament emission current. With plasma in the device, the grains charge both positively and negatively.

• OSTI ID: 7112636
• Journal Information: IEEE Transactions on Plasma Science (Institute of Electrical and Electronics Engineers); (United States), Vol. 22:2; ISSN 0093-3813
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC DUST
CHARGE COLLECTION
EARTH MAGNETOSPHERE
EXPERIMENTAL DATA
PARTICLE SIZE
PLASMA
SILICON CARBIDES
CARBIDES
CARBON COMPOUNDS
DATA
DUSTS
EARTH ATMOSPHERE
INFORMATION
NUMERICAL DATA
SILICON COMPOUNDS
SIZE
661320* - Auroral
Ionospheric
& Magnetospheric Phenomena- (1992-)