Accuracy of theory for the breathing oscillation of a complex plasma disc

Accuracy of theory for the breathing oscillation of a complex plasma disc

Sheridan T E

Journal of Physics D-Applied Physics

2006

2006-02

A complex plasma disc (CPD) is a stable two-dimensional arrangement of it particles, each with mass in and charge q, confined by a parabolic well and interacting through a shielded Coulomb force (i.e. a Yukawa potential). It is shown that the breathing frequency of a CPD is accurately predicted by an analytical theory in which it is assumed that the breathing mode corresponds to a uniform expansion and contraction of the disc. Predictions of the theory are compared with exact eigenmode computations for n = 2-100 particles with Debye shielding parameters K = 0.1-10. The breathing frequency is predicted exactly for n <= 8 particles due to symmetry. For n > 8 particles, the error in the square of the breathing frequency is always less than 0.4% and increases approximately linearly with K. The utility of this theory for analysing experimental data is illustrated by finding the average particle charge and Debye length for a disc with n = 40 particles.

2-dimensional clusters; dusty plasma; mode; Physics; sheath

Journal Article

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693-699

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