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In this article, the propagation of ion-acoustic shock and periodic waves along with their dynamical analysis around the supercritical values is studied in a (1 + 1)-dimensional collisionless negative ions plasma system comprising of inertia SF 6 − with mass m − i and temperature T − i , inertia K+ with mass m + i and temperature T + i and inertialess non-extensive distributed electrons. By considering the appropriate starching coordinates and expansion of perturbation quantities, the Burgers-type equation with quartic nonlinearity is derived. Using the traveling wave transformation, a planar dynamical system is formed. The phase portrait is drawn and the associated nonlinear waves are analyzed. The research presented could be beneficial for understanding and forecasting localized electrostatic disturbances in the F- and D-layers of Earth's ionosphere as well as for guiding future experimental investigations in plasma laboratories. [ABSTRACT FROM AUTHOR]

In this paper, the nonlinear propagation of electrostatic collisional among multi-solitons around the critical values along with their corresponding phase shifts and collision between two rouge waves propagating toward each other is studied in an unmagnetized plasma environment. Using the concept of Hirota's bilinear method, the useful forms of multi-solitons solutions of the coupled modified Korteweg–de Vries equations (mKdVEs) are determined. Furthermore, the coupled nonlinear Schrödinger equations (NLSEs) are derived from mKdVEs using the appropriate starching coordinates. The analytic solutions of different orders for the coupled NLSEs are also presented. The effects of the parameters related to the plasma environment on the electron acoustic scattered solitons, phase shifts and scattered rouge waves are analyzed. The proposed results provide the theoretical guidance to understand the propagation characteristics of collisional solitons, and their phase shifts around the critical values and collisional rouge waves in the modulated ranges. [ABSTRACT FROM AUTHOR]

Progress in understanding the propagation of dust ion acoustic shock waves for the super critical values of any specific parameter which accompany an unmagnetized collisionless four‐component dusty multi‐ion nonextensive plasma is presented. To accomplish this goal, the formation of modified Burgers‐type equation having quartic nonlinearity via the reductive perturbation method and its analytical solution is yielded for the first time. It is found that the compressive electrostatic shocks are supported not only around the super critical values but also at the super critical values of the specific parameters. The presented results would be applicable to comprehend wave propagation in interplanetary plasmas and laboratory plasmas. [ABSTRACT FROM AUTHOR]

The collisionless magnetized complex plasma (MCP) is considered to describe the nonlinear oblique propagation of dust-ion acoustic (DIA) shock wave and oscillatory wave having periodicity due to the impact of plasma parameters. Such plasma is composed of the dynamic ions having viscous influence, (α, q)-velocity distributed electrons, and static positive or negative dust charged particles. By implementing only the expansion of perturb quantities, the Burgers equation (BE) having quadratic nonlinearity (QN), cubic nonlinearity (CN), and composition of QN and CN are derived. Based on the useful exact solutions of these equations, the effect of physical parameters on the propagation of DIA shock wave, DIA oscillatory wave having periodicity and DIA double layer are discussed. It is found that the plasma system supports the shock and periodic wave excitations with both positive and negative polarity described by BE having QN. In addition, BE having CN supports shock and periodic wave excitations with only positive polarity. BE having a composition of QN and CN supports both shock wave excitations and double layer as well as both left to right and right to left propagating oscillatory waves having periodicity. The presented results would be applicable to space MCP regimes and further experimental verification. [ABSTRACT FROM AUTHOR]

The head-on collision between two-counter-propagating electron acoustic solitons and double layers (DLs) in an unmagnetized collisionless multi-species plasma consisting of inertial cold electron fluid and (α, q)-distributed hot electrons and positrons has been analyzed with the stationary background of massive positive ions. For nonlinear analysis of colliding wave phenomena, the coupled Korteweg–de Vries equation (KdVE), modified KdVE (mKdVE), and standard Gardner equation have been derived by adopting the extended Poincaré–Lighthill–Kuo technique. The effect of non-dimensional parameters on the collisional KdV, mKdV, and Gardner solitons (GSs) and DLs has been examined in detail by considering the limiting cases of (α, q)-distributions. It is found that the plasma model supports (i) the compressive and rarefactive collisional KdV solitons and GSs, (ii) only compressive mKdV solitons, and (iii) only rarefactive collisional DLs. The rarefactive collisional solitons are more affected by nonextensivity and the increase of the temperature of electrons than their compressive counterpart, whereas the rarefactive collisional DLs only existed in the presence of nonthermality. [ABSTRACT FROM AUTHOR]

The work explores the optical wave solutions along with their graphical representations by proposing the coupled spatial-temporal fractional cubic-quartic nonlinear Schrödinger equation with the sense of two fractal derivatives (beta and conformable derivative) and Kerr law nonlinearity for birefringent fibers. The new extended direct algebraic method for the first time is implemented to achieve this goal. Many optical solutions are listed along with their existence criteria. Based on the existence criteria, the cubic-quartic bright, and singular optical soliton, periodic pulse, and rouge wave profiles are supported in birefringent fibers with the influence of both beta and conformable derivative parameter. [ABSTRACT FROM AUTHOR]

This article investigates the dust ion acoustic multi-shock wave excitations in weakly relativistic multi-component plasma by assuming nonthermal, nonextensive electrons and positrons, relativistic ion fluid having kinetic viscosity and immobile dust. Burgers equation is derived to investigate such excitations by applying the reductive perturbation method. The exponential functions are directly implemented to determine the novel multi-shock wave solution of Burgers equation. The dust ion acoustic (DIA) multi-shock wave excitations are investigated systematically to reveal the effects of parameters, namely, viscosity coefficient of ions, positron to electron density ratio, immobile dust to electron density ratio, ion to electron temperature ratio, electron to positron temperature ratio, and relativistic streaming factor of ions in the presence of nonthermal, nonextensive, and concurrently acting nonthermal and nonextensive electrons as well as positrons. It is found that the amplitudes and widths of not only single, but also multi-shock wave compressive and rarefactive electrostatic potential structures are changed with the influence of all plasma parameters. The obtained results may be useful to analyze the nature of DIA multi-shock wave phenomena in various astrophysical as well as space environments (particularly, in pulsar relativistic winds with supernova ejecta) and future studies in plasma laboratory. [ABSTRACT FROM AUTHOR]

Head-on collision between ion acoustic shock waves (IASWs) and the consequences after collision are investigated considering the plasma system to be consisting of relativistic warm ions and nonextensive electrons and positrons, taking into account the effects of nonlinearity and dispersion. Two-sided KdV-Burger equations are derived employing the extended Poincar e ´ -Lighthill-Kuo method. The results reveal that the plasma parameters are responsible for the modification of the structures along with phase shifts of the shock waves. The nonlinearity effects on IASWs in a highly relativistic regime (HRR) become pronounced rather than the weakly relativistic regime (WRR). The phase shifts of IASWs are enhanced by the relativistic streaming factor and superthermality. The electrostatic IASWs become rarefactive depending on temperatures, kinematic viscosity, and superthermality in both WRR and HRR. The amplitudes of IASWs are increasing for WRR but decreasing for HRR due to increasing ion thermal velocities. Besides, the amplitudes of the solitons are detaining due to the increase in the positron concentration for the depopulation of ions. [ABSTRACT FROM AUTHOR]

Propagation characteristics and interaction phenomena among the dust acoustic (DA) solitons in unmagnetized dusty plasmas are studied. The plasma is composed of negatively charged mobile dust, Boltzmann distributed electrons, and nonthermally distributed cold and hot ions. The extended Poincaré-Lighthill-Kuo method is employed to derive the two-sided Korteweg-de Vries (KdV) equations. The solutions of the KdV equations are constructed using the Hirota bilinear method both for single- and multi-solitons. The phase shifts are determined for the interactions among the two-, four-, and six-DA solitons. The effects of plasma parameters on the head-on collisions of the DA single- and multi-solitons and their corresponding phase shifts are investigated. [ABSTRACT FROM AUTHOR]

A comparative study of the interactions between nonlinear ion acoustic solitary waves (IASWs) propagating toward each other, and the electrostatic nonlinear propagation of IASWs, both for the weakly and relativistic regimes consisting of relativistic warm ions, nonthermal electrons and positrons, is carried out. Two-sided Korteweg--de Vries (KdV) equations are derived using the extended Poincar-e-Lighthill-Kuo (PLK) method to reveal the physical issues concerned. The effects of positron concentration, ion-electron temperature ratio, electron-positron temperature ratio, relativistic streaming factor, the population of electron, and positron nonthermality on the electrostatic resonances and their phase shifts are investigated for both regimes. It is found that the plasma parameters significantly modify the phase shifts, electrostatic resonances, hump-shaped electrostatic potential profiles, and the electric fields on the nonlinear propagation characteristics of IASWs. The results obtained may be useful for clarifications of interaction between IASWs in astrophysical and laboratory plasmas, especially in pulsar magnetosphere, laser produced, inertial confinement plasmas, and pulsar relativistic winds with supernova ejecta that produce nonthermal electrons, positrons and relativistic ions. Published by AIP Publishing. [ABSTRACT FROM AUTHOR]

Two-dimensional three-component plasma system consisting of nonextensive electrons, positrons, and relativistic thermal ions is considered. The well-known Kadomtsev-Petviashvili-Burgers and Kadomtsev-Petviashvili equations are derived to study the basic characteristics of small but finite amplitude ion acoustic waves of the plasmas by using the reductive perturbation method. The influences of positron concentration, electron-positron and ion-electron temperature ratios, strength of electron and positrons nonextensivity, and relativistic streaming factor on the propagation of ion acoustic waves in the plasmas are investigated. It is revealed that the electrostatic compressive and rarefactive ion acoustic waves are obtained for superthermal electrons and positrons, but only compressive ion acoustic waves are found and the potential profiles become steeper in case of subthermal positrons and electrons. [ABSTRACT FROM AUTHOR]

Atmospheric pressure H2O/O2 gliding arc plasma is generated by a 88 Hz, 6kV AC power supply. The properties of the produced plasma are investigated by optical emission spectroscopy. The relative intensity, rotational, vibrational, excitation temperatures and electron density are studied as a function of applied voltage, electrode spacing, and oxygen flow rate. The rotational and vibrational temperatures are determined simulating the OH(A²Σ+(v" = 0) → X²Π(v' = 0)) bands with the aid of LIFBASE simulation software. The excitation temperature is obtained from the CuI transition taking non-thermal equilibrium condition into account employing intensity ratio method. The electron density is approximated from the Hα Stark broadening using the Voigt profile fitting method. It is observed that the rotational and vibrational temperatures decrease with increasing electrode spacing and O2 flow rate, but increase with the applied voltage. The excitation temperature is found to increase with increasing applied voltage and O2 flow rate, but decrease with electrode spacing. The electron density increases with increasing applied voltage while it seems to be in a downward trend with increasing electrode spacing and O2 flow rate. [ABSTRACT FROM AUTHOR]

The theoretical and numerical studies have been investigated on the nonlinear propagation of electrostatic ion-acoustic waves (IAWs) in an un-magnetized Thomas–Fermi plasma system consisting of electron, positrons, and positive ions for both of ultra-relativistic and non-relativistic degenerate electrons. Korteweg-de Vries (K-dV) equation is derived from the model equations by using the well-known reductive perturbation method. This equation is solved by employing the generalized Riccati equation mapping method. The hyperbolic functions type solutions to the K-dV equation are only considered for describing the effect of plasma parameters on the propagation of electrostatic IAWs for both of ultra-relativistic and non-relativistic degenerate electrons. The obtained results may be helpful in proper understanding the features of small but finite amplitude localized IAWs in degenerate plasmas and provide the mathematical foundation in plasma physics. [ABSTRACT FROM AUTHOR]

The Korteweg-de Vries Burgers ðKdVBÞ-like equation is derived to study the characteristics of nonlinear propagation of ion acoustic solitions in a highly relativistic plasma containing relativistic ions and nonextensive distribution of electrons and positrons using the well known reductive perturbation technique. The KdVB-like equation is solved employing the Bernoulli's equation method taking unperturbed positron to electron concentration ratio, electron to positron temperature ratio, strength of nonextensivity, ion kinematic viscosity, and highly relativistic streaming factor. It is found that these parameters significantly modify the structures of the solitonic excitation. The ion acoustic shock profiles are observed due to the influence of ion kinematic viscosity. In the absence of dissipative term to the KdVB equation, compressive and rarefactive solitons are observed in case of superthermality, but only compressive solitons are found for the case of subthermality. [ABSTRACT FROM AUTHOR]

The exp(Φ(η))-expansion method is applied to find exact traveling wave solutions to the (2+1)-dimensional Boussinesq equation which is an important equation in mathematical physics. The traveling wave solutions are expressed in terms of the exponential functions, the hyperbolic functions, the trigonometric functions and the rational functions. The procedure is simple, direct and constructive without the help of a computer algebra system. The applied method will be used in further works to establish more new solutions for other kinds of nonlinear evolution equations arising in mathematical physics and engineering. [ABSTRACT FROM AUTHOR]

In this paper, we apply the novel {G'/G)-expansion method to solve nonlinear evolution equations. We investigates the new exact traveling wave solutions of the complex coupled Higgs field equations. This method proved to be very effective in treating nonlinearities as in the case of the prototype considered. Not only does the method provide the general solutions, but also detects special types of exact solutions, such kinks, solitons, cuspon, peakons, periodic waves, and bell type solitary waves. The various waves propagations schemes detected through the novel (G'/G)-expansion method, and their consequent dynamics, are illustrated in graphical representations. [ABSTRACT FROM AUTHOR]

A series of experiments were conducted to investigate the effects of moving, normal and carbon dioxide-free air on the stomata within porometer cups attached to the illuminated leaves of Datura stramonium, Pelargonium zonale, Duranta plumieri and Clerodendron inerme. A marked opening stomatal response was obtained in Datura and Pelargonium on changing to carbon dioxide-free air. In general no such response was established in Duranta and Clerodendron. Indications of even an opposite closing effect were shown in the case of Duranta. The present results seem to disprove the reduction of carbon dioxide by photosynthesis as the major factor controlling the wide stomatal opening within a porometer cup. The possibility of a humidity effect is also suggested. [ABSTRACT FROM AUTHOR]

The oblique plane waves with their dynamical behaviors for a (2+1)-dimensional nonlinear Schrödinger equation (NLSE) having beta derivative spatial-temporal evolution are investigated. In order to study such phenomena, NLSE is converted to a nonlinear ordinary differential equation with a planar dynamical system by considering the variable wave transform with obliqueness and the properties of the beta derivative. Some more new general forms of analytical solutions, like bright, dark, singular, and pure periodic solutions of NLSE are constructed by employing the auxiliary ordinary differential equation method and the extended simplest equation method. The effect of obliqueness and beta derivative parameter on several types of wave structures along with the phase portrait diagrams are reported by considering some special values of parameters for the existence of attained solutions. It is found that the planar dynamical system is not supported by any type of orbit for Θ = 45 0 . It is also confirmed from the obtained solutions that no plane waves are generated for Θ = 45 0 . The presented studies on bifurcation analysis and analytical solutions for (2+1)-dimensional NLSE would be very useful to understand the physical scenarios of nonlinear spin dynamics in magnetic materials for Heisenberg models of ferromagnetic spin chains., Competing Interests: The authors declare no conflict of interest., (© 2022 The Author(s).)