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[en] The damping rate, as a function of the wave amplitude, of an electron plasma surface wave is deduced and discussed. copyright 1997 American Institute of Physics

[en] Plasma wave instabilities under external fields are studied. (author). 3 refs., 4 figs

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[en] The evolution of super rogue wave having amplitude ∼5 times the background wave has been observed in multicomponent plasma with critical concentration of negative ions in a double plasma device. In normal electron-ion plasma the ion acoustic solitons are described by the Korteweg-de Vries (KdV) equation. At a critical concentration of negative ions, the ion acoustic modified KdV solitons are found to propagate. Multicomponent plasma also supports the propagation of a special kind of soliton namely 'Peregrine soliton' at critical concentration of negative ions. Peregrine soliton is a doubly localized solution of the nonlinear Schrodinger equation (NLSE) having amplitude 3 times the background carrier wave. In a double plasma device, ion-acoustic Peregrine soliton is excited by applying slowly varying amplitude modulated continuous sinusoidal signal to the source anode and described by the rational solution of NLSE. The ion acoustic wave is modulationally unstable in multicomponent plasma with critical concentration of negative ions and an initial modulated wave perturbation is found to undergo self-modulation to form localized structures by balancing the nonlinearity with the dispersion. In presence of higher order nonlinearity, propagation of a high amplitude (∼5 times of background carrier wave) ion acoustic Peregrine soliton has been observed experimentally. The existence of such types of higher order wave has been reported in other dispersive media. These are considered to be the prototype of super rogue wave in deep water. In this work, experimental results on the evolution of super rogue wave in a double plasma device are presented and compared with the numerical solution of NLSE. (author)

[en] Some forced planar limit-cycle systems can be described, when the driving force is impulsive, by circle maps, in the fast relaxation limit. We have considered a lattice of such maps, locally and globally coupled, and study its spatial-temporal dynamics, with emphasis on the synchronization of periodic and chaotic oscillations. (author). 8 refs., 5 figs

[en] The possible smoothing effect that diffusion has on steep plasmapause density gradients is examined for diffusion estimated from (a) the Bohm diffusion coefficient and (b) scattering by observed electrostatic waves. For characteristic plasma temperatures and magnetic fields at an L = 4 plasmapause, the (equatorial) perpendicular Bohm diffusion coefficient is approximately D_B = 0.12 x 10^-₄ R_E2 /h. The estimate for diffusion resulting from scattering by observed electrostatic waves is much lower: D_{perpendicular,E} = 0.27 x 10^-₇ R_E2 /h. However, this diffusion rate may be too small an estimate if, as is probable, the wave amplitudes are significantly higher for steep plasmapauses. Thus the effects are negligible for most considerations of macroscopic plasmapause dynamics but could be significant in limiting drift wave instabilities and similar phenomena which are driven by the steepness of the plasmapause density gradient. If Bohm diffusion is operative, the minimum persistent plasmapause scale length should be of the order 10^-₂ R_E, or approx.60 km

[en] K-entropy is calculated for nonideal plasmas by molecular dynamics methods for both electrons and ions. Various time intervals are treated. (author)

No abstract available