Criterion for bulk behavior of a Yukawa disk
- Department of Physics and Astronomy, Ohio Northern University, Ada, Ohio 45810 (United States)
A Yukawa disk is a two-dimensional system of n particles interacting through a Yukawa potential (i.e., a screened Coulomb or Debye potential) with Debye length {lambda} and confined in an isotropic parabolic well where the single-particle oscillation frequency is {omega}{sub 0}. One example of a Yukawa disk is a two-dimensional complex (dusty) plasma. The emergence of bulk (macroscopic) behavior in a strongly coupled Yukawa disk is studied by considering the dependence of the normalized, squared breathing frequency {omega}{sub br}{sup 2}/{omega}{sub 0}{sup 2} (i.e., the bulk modulus) on n, {lambda}, the disk radius R{sub 0}, and the nearest-neighbor distance a. An analytical expression for {omega}{sub br}{sup 2}/{omega}{sub 0}{sup 2} is derived for the bulk limit, R{sub 0}>>{lambda}, with a/{lambda} finite. In the plasma regime a < or approx. {lambda}, so that each particle interacts with many other particles, {omega}{sub br}{sup 2}/{omega}{sub 0}{sup 2}{approx_equal}4 independent of a/{lambda}. In the nearest-neighbor regime a > or approx. {lambda}, short-range interactions dominate and {omega}{sub br}{sup 2}/{omega}{sub 0}{sup 2}{approx}a/{lambda}. Computational solutions of the model for n=100-3200 particles approach the theoretical bulk limit as n increases. Solutions with n=3200 and a/{lambda} between 0.25 and 0.5 are found to give the best approximation to an unbounded plasma.
- OSTI ID:
- 20974867
- Journal Information:
- Physics of Plasmas, Vol. 14, Issue 3; Other Information: DOI: 10.1063/1.2713722; (c) 2007 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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