Measurements of electric charge and screening length of microparticles in a plasma sheath
- Department of Physics, Faculty of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan)
An experiment is described in which microparticles are levitated within a rf sheath above a conducting plate in argon plasma. The microparticles forming a two-dimensional crystal structure are considered to possess Debye screening Coulomb potential {phi}(r)=(Q/4{pi}{epsilon}{sub 0}r)exp(-r/{lambda}), where Q is the electric charge, r is distance, and {lambda} is the screening length. When the crystal structure is slanted with an angle {theta}, a particle experiences a force Mg sin {theta}, where M is the mass of the particle and g is acceleration due to gravity, which must be equal to the Debye screened Coulomb force from other particles. By changing {theta}, relations for {lambda}(Q) are measured. The screening length {lambda} and Q are determined uniquely from the crossing points of several relations. The electric charge Q is also estimated from a floating potential measured with a probe. The measured {lambda} is nearly equal to an ion Debye length.
- OSTI ID:
- 21277045
- Journal Information:
- Physics of Plasmas, Vol. 16, Issue 4; Other Information: DOI: 10.1063/1.3112702; (c) 2009 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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