Numerical simulation of wave propagation in crystallized dusty plasmas: One dimensional model

A numerical code has been developed to study the wave propagation in crysta llized dusty plasmas. In the one-dimensional model, we model a very long sy stem by. a finite number of dusty particles with the periodic boundary cond ition. Each simulation is characterized by kappa, the ratio of the inter-pa rticle separation at equilibrium over the Debye length, and Gamma, the rati o of the characteristic inter-particle Coulomb potential energy over the th ermal energy of the particles. Viscosity, finite-size effect and the therma l motion are ignored. Some interesting results have emerge from the systema tic simulations: 1. The phase velocity of the wave propagation is nearly in dependent of its wave number at large inter-particle separation, kappa > 2. 0. Thus the disturbance of the Gaussian shape propagates like a solitary wa ve. 2. The propagation speed v of a Gaussian disturbance is strictly propor tional to the square root of Gamma. 3. When kappa less than or equal to 2.0 , the propagation speed v (expressed in terms of the thermal speed) of dist urbance is very well fitted by v = root Gamma/196 (-17.4 + 41.6/root kappa). We further observe that solitary-wave-like propagation will appear when onl y the nearest neighbor force is effective. As the inter-particle separation becomes smaller, more interparticle forces other than the nearest neighbor force become effective, resulting in the widening of the difference betwee n the phase velocities of low and high frequency waves. Therefore, this sol itary-wave-like behavior does not appear in the wave propagation for small particle separation. We apply the result of our simulations to examine the polar mesosphere summer echo (PSME) event reported by Ref 1 [Alcala et al., Radio Science, 30, 1205 (1995)].