Nonlinear Dynamics and Chaos in Gas Discharge Systems (original) (raw)
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Physics of Plasmas, 2014
Intermittent chaos was observed in a glow discharge plasma as the system evolved from regular type of relaxation oscillations (of larger amplitude) to an irregular type of oscillations (of smaller amplitude) as the discharge voltage was increased. Floating potential fluctuations were analyzed by different statistical and spectral methods. Features like a gradual change in the normal variance of the interpeak time intervals, a dip in the skewness, and a hump in the kurtosis with variation in the control parameter have been seen, which are strongly indicative of intermittent behavior in the system. Detailed analysis also suggests that the intrinsic noise level in the experiment increases with the increasing discharge voltage. An attempt has been made to model the experimental observations by a second order nonlinear ordinary differential equation derived from the fluid equations for an unmagnetized plasma. Though the experiment had no external forcing, it was conjectured that the intrinsic noise in the experiment could be playing a vital role in the dynamics of the system. Hence, a constant bias and noise as forcing terms were included in the model. Results from the theoretical model are in close qualitative agreement with the experimental results. V C 2014 AIP Publishing LLC. [http://dx.
CHAOS AND HYPERCHAOS IN A SYMMETRICAL DISCHARGE PLASMA: EXPERIMENT AND MODELLING
În această lucrare prezentăm rezultate experimentale şi modelări computaţionale ale tranziţiei haos-hiperhaos în plasma unui sistem format din două descărcări electrice care se produc în acelaşi tub de sticlă şi au geometrii şi parametri identici. Caracteristicile plasmei din spaţiul inter-anodic sunt controlate de o tensiune de polarizare aplicată pe cei doi anozi. Dinamicile plasmei sunt investigate prin intermediul fluctuaţiilor de curent. Pentru un anumit domeniu al polarizării inter-anodice continue, se observă o tranziţie haos-hiperhaos. Prezentăm un model computaţional constând din trei oscilatori neliniari cuplaţi care conduce la rezultate în bună concordanţă cu cele experimentale.
Phase Synchronization In a Plasma Discharge Driven by a Chaotic Signal
AIP Conference …, 2003
£ Department of Physics, Illinois State University, Normal, Illinois 61790 Nonlinear Dynamics Lab., Dept. of Physics, University of Miami, Coral Gables, Florida 33146 ££ University of Oxford, Department of Engineering Science, Parks Road, OX1 3PJ, UK Nonlinear ...
Chaos and turbulence studies in low- plasmas
Plasma Physics and Controlled Fusion, 1997
This paper describes recent experimental investigations of the nonlinear dynamics of collisional current-driven drift waves in a linear low-β discharge. It is shown that the bias of an injection grid leads to rigid-body rotation of the cylindrical plasma column that strongly destabilizes the drift waves, thus providing a control parameter for the drift-wave dynamics. In the nonlinear regime, when the control parameter is increased, the transition scenario from stability to weakly developed turbulence is studied. Two successive Hopf bifurcations, a modelocked state and its gradual destabilization to chaos and finally turbulence follow the classical Ruelle-Takens transition scenario known from neutral fluids. In addition to the temporal dynamics, the spatiotemporal evolution of drift waves is studied by means of circular Langmuir probe arrays with high spatial and temporal resolution. With each Hopf bifurcation, a drift-mode onset is associated and the bifurcation from quasi-periodicity to mode locking corresponds to the transition from non-resonant to resonant mode interaction. The mode-locked state forms a persistent spatiotemporal pattern that is destabilized by the occurrence of defects. In contrast, the turbulent state is a fully disordered, intermittent state.
Phase Synchronization of Chaos in a Plasma Discharge Tube
International Journal of Bifurcation and Chaos, 2000
Experimental phase synchronization of chaos is demonstrated for a plasma discharge tube subject to a high dc voltage (800-900 V), and paced with a low amplitude (less than 1 V) wave generator.
Chaotic current oscillations with broadband1/f α spectrum in a glow discharge plasma
Chaos Solitons & Fractals, 1996
We have observed self-generated chaotic current oscillations in the plasma of a helium glow discharge. The S(fl power density spectrum of the current signal exhibited characteristic S(f) a l/f" dependence over a wide range of frequencies with an exponent of IY = 4.3. The correlation dimension of the system determined from the correlation sums of the current signal was found to be Dz = 6.3. This value of 02 is in good agreement with the theoretically predicted dimension, corresponding to fully developed turbulence.
Evidence of homoclinic chaos in the plasma of a glow discharge
Physical Review Letters, 1992
Homoclinic chaos is sho~n to occur in the electric current measured on an electrical discharge in argon. We report a clear sequence of four hesitations followed by a reverse period doubling. The experimental signals are used io construct return time-and time of fl-igh-t maps that evidence a Shilnikov scenario in the system. PACS numbers: 52.3S.Py, S2.80.Hc Apart from the most known routes to chaos like period doubling, intermittency, quasiperiodicity, etc. [1], different transition sequences from periodic to chaotic patterns have also been observed. An example of such are the so-called alternating periodic chaotic -(APC) sequences [2]
Experimental Real-Time Phase Synchronization of a Paced Chaotic Plasma Discharge
Physical Review Letters, 2000
Experimental phase synchronization of chaos in a plasma discharge is studied using a phase variable lift technique (i.e., phase points separated by 2p are not considered as the same). Real-time observation of synchronized and unsynchronized states is made possible through a real-time sampling procedure. Parameter space regions of synchronization and unsynchronization are identified, and a set of equations is suggested to model the real plasma circuit. PACS numbers: 05.45.Xt, 52.35.Ra Given a chaotic oscillator for which an angle coordinate can be suitably introduced as a state space variable, it is often the case that the phase of this oscillator synchronizes with the phase of an external periodic perturbation, or pacer . That is, the phase difference between the chaotic oscillator and the pacer remains bounded by some appropriate constant fraction of 2p for all time, depending on the values of the amplitude and frequency of the pacer . In this phase synchronized state, the oscillator remains chaotic, but its phase is in step with that of the pacing signal.
Nonlinear Dynamics and Chaos in Space Plasmas
Progress of Theoretical Physics Supplement, 2000
The theory and observation of nonlinear wave coupling phenomena in solar-system plasmas are reviewed. Rocket and satellite observations have p r o vided evidence of nonlinear wave interactions in space plasmas, in particular, in relation to the generation and propagation of radio waves in solar corona, interplanetary medium and Earth's magnetosphere. These radio waves represent the electromagnetic signature of solar-terrestrial coupling and are useful for forecasting and monitoring of space weather. Nonlinear wave-wave coupling in plasmas can be modeled as a dynamical system of coupled oscillators involving one, two or higher-order wave triplets. For a three-wave dissipative system, the temporal transition from order to chaos may e v olve via period doubling or intermittence. For a four-wave Hamiltonian system involving two coupled wave triplets, the spatiotemporal transition from order to chaos is analyzed using the concepts of stable and unstable homogeneous manifolds. ) E-mail address: achian@dge.inpe.br ) Current address: INPE -Brazil.
CHAOTIC OSCILLATIONS IN MAGNETOHYDRODYNAMICS
In this paper first of all DC glow discharge plasma is characterized by finding out plasma parameters. This involves study of Paschen curve and Langmuir probe characteristic. After that floating potential fluctuations are obtained by using Langmuir probe at different values of pressure of gas, external magnetic field and discharge voltage. The analysis of these nonlinear oscillations involves nonlinear time series analysis. Analysis is carried out by several techniques like determining correlation dimensional analysis, Fourier spectrum analysis, rescaled range analysis (for Hurst exponent), determining Largest Lyapunov exponent (by Rosenstein method), 0-1 test for chaos etc.