The experimental observation of Peregrine solitons in a multicomponent plasma with the critical concentration of negative ions is reported. A slowly amplitude modulated perturbation undergoes self-modulation and gives rise to a high amplitude localized pulse. The measured amplitude of the Peregrine soliton is 3 times the nearby carrier wave amplitude, which agrees with the theory. The numerical solution of the nonlinear Schrödinger equation is compared with the experimental results.

The collision between two counterpropagating dust acoustic solitary waves in a strongly coupled dusty plasma has been observed. The measured velocity and width of the solitary wave agree with the solution of the Korteweg-de Vries equation derived by using the generalized hydrodynamic model. The two counterpropagating solitary waves of equal amplitude merge into a single pulse with twice the individual soliton amplitude and then pass through each other. The solitons suffer a small time delay in propagation after collision. The measured delay time obtained from their trajectories is also presented.

[1] The evolution of hole Peregrine soliton (appearing as a deep trough between two crests) from ion-acoustic perturbations excited in a multicomponent plasma with critical density of negative ions has been observed. The observed soliton is described by the rational solution of the cubic nonlinear Schrödinger equation, which can appear as an isolated high peak or a deep hole depending on the phase of the underlying carrier wave relative to the envelope. The measured amplitude of the hole Peregrine soliton (depth from crest to trough) is found to be more than twice the background wave height. The experimental observations are compared with the theoretical results obtained from the solution of the cubic nonlinear Schrödinger equation. The frequency spectrum of the Peregrine soliton is analyzed and found to be triangular in shape.Citation: Sharma, S. K., and H. Bailung (2013), Observation of hole Peregrine soliton in a multicomponent plasma with critical density of negative ions,

The experimental observation of second order ion acoustic Peregrine breathers in multicomponent plasma with negative ions is reported. A long wavelength initial perturbation on a continuous carrier frequency ∼0.5 ωpi (where ωpi is the ion plasma frequency) of finite amplitude is found to undergo self-modulation due to the interplay between nonlinear dispersive effect and group velocity dispersion because of modulational instability. Wave energy focusses to a smaller localized and isolated group of waves within the packet with amplitude amplification up to 5 times of the background carrier wave. The experimental results are compared with second order breather solution of nonlinear Schrodinger equation. The wavelet analysis and fast Fourier transform analysis of the experimental time series data indicate strong nonlinear evolution (wave energy focusing and spectral broadening) conforming to the formation of second order Peregrine solitons.

Dusty plasma with a nanometer size dust grain is produced by externally injecting carbon nanopowder into a radio frequency discharge argon plasma. A self-excited dust acoustic wave with a characteristic frequency of ∼100 Hz is observed in the dust cloud. The average dust charge is estimated from the Orbital Motion Limited theory using experimentally measured parameters. The measured wave parameters are used to determine dusty plasma parameters such as dust density and average inter particle distance. The screening parameter and the coupling strength of the dusty plasma indicate that the system is very close to the strongly coupled state.