Turing structures in dc gas discharges

Popescu, Ştefan

doi:10.1209/epl/i2005-10392-7

Cited by 8 publications

(8 citation statements)

References 22 publications

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“…In what follows, we present a series of experimental data obtained when examining the dynamics of non-concentric multiple structures in plasma, with particular behavior. For this case, the nonlinear dynamics analysis emphasizes a stable behavior of the fireballs oscillations [6][7][8]. Using the SR, a theoretical model was built and its results were found to be in good agreement with our experimental data.…”

Section: Introductionsupporting

confidence: 55%

Experimental and theoretical evidence for the chaotic dynamics of complex structures

et al. 2013

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This paper presents the experimental results on the formation, dynamics and evolution towards chaos of complex space charge structures that emerge in front of a positively biased electrode immersed in a quiescent plasma. In certain experimental conditions, we managed to obtain the so-called multiple double layers (MDLs) with non-concentric configuration. Our experiments show that the interactions between each MDL's constituent entities are held responsible for the complex dynamics and eventually for its transition to chaos through cascades of spatio-temporal sub-harmonic bifurcations. Further, we build a theoretical model based on the fractal approximation (scale relativity theory) in order to reproduce the experimental results (plasma self-structuring and scenario of evolution to chaos). Comparing the experimental results with the theoretical ones, we observe a good correlation between them.

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Section: Introductionsupporting

confidence: 55%

Experimental and theoretical evidence for the chaotic dynamics of complex structures

et al. 2013

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“…The relation to biology is stressed in [80] and the references therein. Similarities between the diffusion-driven mechanism of biological differentiation, proposed by Turing in 1952 [81] and pattern formation in gas-discharge are mentioned in [82].…”

Section: Introductionmentioning

confidence: 60%

Synergetic aspects of gas-discharge: lateral patterns in dc systems with a high ohmic barrier

Purwins¹,

Stollenwerk

2014

Plasma Phys. Control. Fusion

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The understanding of self-organized patterns in spatially extended nonlinear dissipative systems is one of the most challenging subjects in modern natural sciences. Such patterns are also referred to as dissipative structures. We review this phenomenon in planar low temperature dc gas-discharge devices with a high ohmic barrier. It is demonstrated that for these systems a deep qualitative understanding of dissipative structures can be obtained from the point of view of synergetics. At the same time, a major contribution can be made to the general understanding of dissipative structures. The discharge spaces of the experimentally investigated systems, to good approximation, have translational and rotational symmetry by contraction. Nevertheless, a given system may exhibit stable current density distributions and related patterns that break these symmetries. Among the experimentally observed fundamental patterns one finds homogeneous isotropic states, fronts, periodic patterns, labyrinth structures, rotating spirals, target patterns and localized filaments. In addition, structures are observed that have the former as elementary building blocks. Finally, defect structures as well as irregular patterns are common phenomena. Such structures have been detected in numerous other driven nonlinear dissipative systems, as there are ac gas-discharge devices, semiconductors, chemical solutions, electrical networks and biological systems. Therefore, from the experimental observations it is concluded that the patterns in planar low temperature dc gas-discharge devices exhibit universal behavior. From the theoretical point of view, dissipative structures of the aforementioned kind are also referred to as attractors. The possible sets of attractors are an important characteristic of the system. The number and/or qualitative nature of attractors may change when changing parameters. The related bifurcation behavior is a central issue of the synergetic approach chosen in the present article. A short review of possible theoretical approaches reveals that a theoretical description of the experimentally observed patterns is far from being satisfactory. Bearing this in mind, a qualitative model of the reaction-diffusion type is considered. Surprisingly enough, this model allows for a qualitative description of almost all fundamental patterns that have been observed experimentally. Also, so far the predictive power of this model is unmatched.

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“…Then, if we divide by dt and neglect the terms which contain differential factors (for details on the method, see [16,17]), (12) may be written under the form…”

Section: Covariant Total Derivative In Drug Release Processmentioning

confidence: 99%

Drug Release Kinetics from Polymer Matrix through Fractal Approximation of Motion

Bācāiţā

Urîtu²,

Popa

et al. 2012

Smart Materials Research

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The present paper analyzes the process of drug release from polymer matrix. This process has been considered as fractal polymer process. Since complexity of physical processes is replaced by fractality, the paper studies the process through fractal approach. In drug dynamics, fractal "diffusion" equation can be obtained through fractal approximation of motion. All experimental release curves have been best demonstrated by Weibull relation (which was, in its turn, also demonstrated). Weibull parameters are related to the fractal dimension of drug release kinetics from a polymer matrix. Such a dimension can characterize and measure the complexity of the system. In the above-mentioned context, some experimental results of our researchers are presented and analyzed by comparing them with Peppas relation, a basic law in the description of drug release kinetics. Consequently, experimental data for Weibull relation are better correlated with certain resulting factors. At the same time, some conclusions regarding the phenomena involved in the process are considered as being based on the approach.

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Turing structures in dc gas discharges

Cited by 8 publications

References 22 publications

Experimental and theoretical evidence for the chaotic dynamics of complex structures

Experimental and theoretical evidence for the chaotic dynamics of complex structures

Synergetic aspects of gas-discharge: lateral patterns in dc systems with a high ohmic barrier

Drug Release Kinetics from Polymer Matrix through Fractal Approximation of Motion

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