Behavior Of Surface Waves Research Articles

Thermally tunable phonon–plasmon polariton modes at hexagonal boron nitride (hBN) and indium antimonide (InSb) interfaces

Abstract This work examines the propagation of thermally tunable phonon–plasmon modes at the interfaces of hexagonal boron nitride (hBN) and isotropic indium antimonide (InSb). Both theoretical modeling and numerical simulations are carried out to analyze the effect of temperature on surface wave behavior. hBN is realized as a polar material via the Lorentzian model, while InSb ismodeled as a temperature-sensitive material (TSM) in the framework of Drude’s model. The possible plasmon–phonon polaritonic interactionsarestudied for the TSM–elliptic type interface and TSM– hyperbolic type interface. It is reported that by varying the temperature, the surface modes can be tuned for the lower and upper Reststrahlen (RS) bands of hBN. The dispersion curve, effective mode index, propagation length, and phase speed are computed for each case under different temperatures. It is concluded that the hBN–InSb-based phonon–plasmon polariton modes are actively tuned by changing the external temperature in the lower and upper RS bands. Surface waves propagating across the interface can be modulated from the terahertz (THz) region to the infrared (IR)region by changing the temperature of InSb. This study will help researchers to design innovative thermo-optical sensors, plasmonic platforms, detectors, and surface waveguides in the THz and IR regions.

Theoretical analysis of surface waves in piezoelectric medium with periodic shunting circuits

The investigations of surface waves in the piezoelectric medium bring out great possibility in designing smart surface acoustic wave (SAW) devices. It is important to study the dispersion properties and manipulation mechanism of surface waves in the semi-infinite piezoelectric medium connected with periodic arrangement of shunting circuits. In this study, the extended Stroh formalism is developed to theoretically analyze the dispersion relations of surface waves under different external circuits. The band structures of both the Rayleigh wave and the Bleustein-Gulyaev (BG) wave can be determined and manipulated with proper electrical boundary conditions. Furthermore, the electromechanical coupling effects on the band structures of surface waves are discussed to figure out the manipulation mechanism of adjusting electric circuit. The results indicate that the proposed method can explain the propagation behaviors of surface waves under the periodic electrical boundary conditions, and can provide an important theoretical guidance for designing novel SAW devices and exploring extensive applications in practice.

Dynamically Triggered Events in a Low Seismically Active Region of Gujarat, Northwest India, during the 2012 Mw 8.6 Indian Ocean Earthquake

ABSTRACT The mainland region of Gujarat, northwest India, is a less investigated region than other parts of India with a low seismicity rate. An Mw >4.7 earthquake has not occurred in this region for 15 yr, and no Mw >5.5 events since 1971. We analyze the local earthquake catalog and waveforms to examine dynamic triggering in the region by the 2012 Mw 8.6 Indian Ocean earthquake, which triggered widespread seismicity globally. Further detection of possibly missing microearthquakes is conducted by applying the matched filter technique to the waveforms. We identify six microearthquakes (∼ML 1.0–2.1) triggered during the surface and coda wave of the 2012 mainshock. Also, an earthquake of Mw 2.6 was likely triggered five hours after the mainshock near Bhavnagar city, because the record since 2006 would indicate such a magnitude event to have only a 0.8% chance of occurring independently any given day. Indeed, only 35 earthquakes with Mw≥2.5 were recorded since 2006 within a 100 km radius of this city. The β-statistics indicate an increase in seismicity and further confirm the triggering. The seismicity rate increased immediately after the 2012 mainshock and continued for three days, indicating a possible delayed triggering. The delayed triggering may be due to the crustal fluid, and/or subcritical crack growth model may be responsible for triggering. Our study suggests that dynamic triggering tends to occur near active faults that have ruptured in ancient times. Other recent earthquakes, for example, 2011 Tohoku-Oki, did not trigger seismicity despite significant peak dynamic stresses values. Investigation of dynamic triggering in regions experiencing infrequent earthquakes can be crucial in understanding the origin of such earthquakes, which can be achieved by grasping the ambient stresses and geodynamic mechanisms in a particular region. Thus, we evaluate character and behavior of high-amplitude surface waves to grasp better the undergoing processes and stress transfer in the intraplate mainland region.

Bottom topography influence on wave transformation by a porous-flexible membrane in a two-layer oblique sea

In a two-dimensional context, the interaction between an oblique gravity wave and a partial porous-flexible membrane barrier in a two-layer fluid with an undulating bottom has been studied using linear wave theory. Two cases (a) wave scattering and (b) wave trapping by porous-flexible membrane barrier in presence of an impermeable sea-wall are discussed. The impact of surface wave, interfacial wave, and the induced energy among these by bottom undulation has been taken into consideration. An approximation technique Mild slope equation (MSE) and Fourier method along with least square approximation have been adopted as a solution technique. The solutions obtained by former methods are matched at interfaces under suitable physical conditions which reduces the problem to algebraic system of equations. This study finds that energy dissipation of surface and interfacial wave acquires an inverse pattern for a given particular gap length between barrier and free-surface. Concave upward bottom is seen to be responsible for less dissipation of surface and interfacial waves. An opposite behavior of surface and interfacial waves on the membrane deformation has been observed. The study carried out in this article holds good potential in deepening our understanding of scattering and trapping of waves by a partial porous-flexible barrier.

Hydrodynamic behavior of a circular floating solar pond with an entrapped two-layer fluid

The resonant behavior in a moonpool of a floating circular solar pond, with an entrapped two-layer fluid, is studied. The problem is solved by applying a domain-decomposition method using eigenfunction matching. The surface- and internal-wave elevations and the hydrodynamic coefficients of a typical floating solar pond under forced heave or surge motion are computed. The effects of density stratification on surface-wave elevation, added mass, and damping coefficients are analyzed. A collection of resonance frequencies of surface and internal waves is examined, together with the corresponding variations of modal shapes. For heave resonance, the surface and internal waves are characterized by axisymmetric sloshing modes, as opposed to antisymmetric sloshing modes under surge resonances. A frozen-mode approximation method that treats the moonpool fluid as a density-stratified solid is developed to estimate piston-mode frequencies. Non-dimensional resonance frequencies corresponding to antisymmetric and axisymmetric sloshing modes are estimated based on the standing-wave approximation and reciprocity relations between surface and internal wavenumbers. Satisfactory agreement between the estimated resonance frequencies and those computed by eigenfunction matching method is achieved. It is found that the first resonance of the internal wave, rather than higher-order resonances, is more likely to affect the surface-wave behavior, whereas resonances of the surface-wave modes have significant effects on the internal waves. Parametric analyses are performed to study the effects of geometry configurations of the pond. It is found that the resonance frequencies of internal waves under forced heave or surge motion decrease with an increasing density ratio.

Investigation of properties of surface modes at the boundary of the DNA origami lattice

In this study, the models for the DNA origami lattice will be investigated. Our aim is to theoretically explore the ways of constructing DNA origami. To achieve this goal the DNA origami structure, consisting of nanowires embedded in a host material, will be treated from the perspective of nanowire metamaterial. Surface plasmon polaritons propagating at the interface of air and DNA metamaterial are analyzed. The dispersion relation is attained using the transfer matrix technique and employing continuity conditions of electric fields and their derivatives at the boundary separating two regions. We have concluded that with numerous nanowires into the metamaterial unit, cell frequencies of surface plasmon polaritons are altered to higher frequencies. In this study, we have studied the effect of modifications of the metamaterial, allowing for the shift of the dispersion maps toward higher frequencies. It is possible to obtain the propagation of spoof plasmons mimicking the behavior of surface waves at lower frequencies. All the properties and parameters of the inorganic metamaterials are applicable to study the phenomenon of the organic substances.

Surface waves propagation in a homogeneous liquid layer overlying a monoclinic half-space

This article includes an analytical investigation of the surface waves propagation in a uniform liquid layer overlying a homogeneous anisotropic (monoclinic) half-space. The waves are allowed to propagate through the interface, i.e., between the layer and the medium. Basic arithmetic procedures are employed to derive the dispersion equation for surface waves propagation. A comprising study is accomplished through numerical estimation to study the behavior of surface waves. Further analysis of surface waves in the absence of a liquid layer manifests that the phase velocity equation loses its dispersity like waves propagation in an isotropic medium. Some particular cases are extracted from the dispersion equation by taking correspondence with the results. Graphical software has been emerged to establish a criterion for the usefulness of several parameters discussed.

Surface wave behavior and refraction simulation on the ocean for the fractional Ostrovsky–Benjamin–Bona–Mahony equation

In this study, we have taken into account the time-fractional Ostrovsky–Benjamin–Bona–Mahony equation, which is a synthesis of the time-fractional Ostrovsky equation and time-fractional Benjamin–Bona–Mahony equations and contains both mathematical and physical properties. Traveling wave solutions are produced by using the Ostrovsky–Benjamin–Bona–Mahony equation that physically sheds light on the incoming wave event on the ocean surface, using the sub-equation and Bernoulli sub-equation function methods. These solutions are presented in hyperbolic, trigonometric, singular and dark (topological) soliton types. With the help of special values given to the coefficients in the solitons obtained, it is associated with the solutions in the literature and it is observed that the solitons produced in this study are more general. Graphs representing the stationary wave at any given moment are presented. The advantages and disadvantages as well as the similarities and differences of the method are discussed in detail. Also, the behavior of the wave and its refraction according to the velocity variable, which is a physically important factor of the traveling wave solution, is analyzed and supported by simulation.

Controlling Surface Plasmon Polaritons Propagating at the Boundary of Low-Dimensional Acoustic Metamaterials

As a novel type of artificial media created recently, metamaterials demonstrate novel performance and consequently pave the way for potential applications in the area of functional engineering in comparison to the conventional substances. Acoustic metamaterials and plasmonic structures possess a wide variety of exceptional physical features. These include effective negative properties, band gaps, negative refraction, etc. In doing so, the acoustic behaviour of conventional substances is extended. Acoustic metamaterials are considered as the periodic composites with effective parameters that might be engineered with the aim to dramatically control the propagation of supported waves. Homogenization of the system under consideration should be performed to seek the calculation of metamaterial permittivity. The dispersion behaviour of surface waves propagating from the boundary of a nanocomposite composed of semiconductor enclosures that are systematically distributed in a transparent matrix and low-dimensional acoustic metamaterial and constructed by an array of nanowires implanted in a host material are studied. We observed the propagation of surface plasmon polaritons. It is demonstrated that one may dramatically modify the properties of the system by tuning the geometry of inclusions.

Zenneck surface wave interconnect with encircle routing for effective inter chip communication

Generally, copper traces are widely used to provide communication among integrated circuits (IC's) of printed circuit board (PCB). In case of high rate data transfer, systems or traces may be damaged due to trace resistivity. In order to overcome this issue, surface wave phenomenon based channel/waveguide is introduced for IC communication in this work. Here, high frequency communication is possible due to both conductivity and dielectric behaviors of surface waves. Use of Zenneck surface instead of copper traces with Encircle Routing (ER) based channel assignment helps to achieve efficient IC communication. High rate of data transfer with low channel dispersion are major benefits of ER based Zenneck surface wave communication. Matlab working platform is used for design analysis by means of attenuation, field decay, skin depth, channel dispersion, power saving rate and signal voltage gain. Also, performance analysis is taken within the frequency range of 50 to 500 GHz to explore a deterministic channel communication between the IC's as an alternate of copper traces.

Dispersive electrostatic waves on a cold magnetized electron gas half-space

Dispersive electrostatic waves on the plane interface between a vacuum and a cold magnetized homogeneous electron gas are predicted for the case where an applied static magnetic field is parallel to the surface and the direction of propagation of the wave, known as Faraday configuration, and also static magnetic field is weakly non-uniform in a direction which is perpendicular to the surface. An expression for dispersion relation of these surface waves is presented based on the Wentzel–Kramers–Brillouin approximation. The dispersion relation shows the importance of the influence of the external static magnetic field gradient on the surface wave behavior.

Study of the effects of stress wave behavior in laser-induced exit-surface damage of fused silica using time-resolved multi-polariscopic imaging

During laser-induced exit-surface damage of fused silica components, strain and stress are generated and accompanied by cracks in the substrate, further deteriorating the component. The authors studied the behaviors of surface and shear waves quantitatively using a time-resolved multipolariscopic imaging system, showing their potential to affect the development of circumferential and longitudinal cracks. When the material received a cumulative shot, a greater stress intensity was observed, and the stress wave had a greater impact on the laser-induced damage. The results indicate that the two stress waves from the cumulated shots dominated the developmental characteristics of the damage morphology.

A note on the Stokes phenomenon in flow under an elastic sheet.

The Stokes phenomenon is a class of asymptotic behaviour that was first discovered by Stokes in his study of the Airy function. It has since been shown that the Stokes phenomenon plays a significant role in the behaviour of surface waves on flows past submerged obstacles. A detailed review of recent research in this area is presented, which outlines the role that the Stokes phenomenon plays in a wide range of free surface flow geometries. The problem of inviscid, irrotational, incompressible flow past a submerged step under a thin elastic sheet is then considered. It is shown that the method for computing this wave behaviour is extremely similar to previous work on computing the behaviour of capillary waves. Exponential asymptotics are used to show that free-surface waves appear on the surface of the flow, caused by singular fluid behaviour in the neighbourhood of the base and top of the step. The amplitude of these waves is computed and compared to numerical simulations, showing excellent agreements between the asymptotic theory and computational solutions. This article is part of the theme issue 'Stokes at 200 (part 2)'.

Applying the New Extended Direct Algebraic Method to Solve the Equation of Obliquely Interacting Waves in Shallow Waters

In this study, the potential Kadomtsev-Petviashvili (pKP) equation, which describes the oblique interaction of surface waves in shallow waters, is solved by the new extended direct algebraic method. The results of the study show that by applying the new direct algebraic method to the pKP equation, the behavior of the obliquely interacting surface waves in two dimensions can be analyzed. This article fairly clarifies the behaviors of surface waves in shallow waters. In the literature, several mathematical models have been developed in attempt to study these behaviors, with nonlinear mathematics being one of the most important steps; however, the investigations are still at a level that can be called ‘baby steps’. Therefore, every study to be carried out in this context is of great importance. Thus, this study will serve as a reference to guide scientists working in this field.

Analysis of Multiple Surface Electromagnetic Waves on the Planner Interface of Hyperbolic Medium and Rugate Filter Having Sinusoidal Refractive Index Profile

This paper presents a canonical boundary value problem to understand the behavior of electromagnetic surface waves propagated on the planar interface of rugate filter and hyperbolic material. The electromagnetic surface waves are generated on the planar interface of two different materials. The hyperbolic materials constructed by making a dyadic negative in columnar thin films. Multiple electromagnetic surface waves were investigated by varying phase of rugate filter form 0 to 180° and wavelength of incident light from 400 to 700 nm. Material’s manufacturing fault is also introduced by adding 0.001 i in refractive index of hyperbolic medium.Propagation of multiple electromagnetic waves were observed on the planar interface of rugate filter and hyperbolic material. In order to verify the existence of surface electromagnetic waves at the interface of hyperbolic medium and rugate filter, electric and, magnetic fields are plotted for different material specifications.

Modulation-resonance mechanism for surface waves in a two-layer fluid system

We propose a Boussinesq-type model to study the surface/interfacial wave manifestation of an underlying, slowly varying, long-wavelength baroclinic flow in a two-layer, density-stratified system. The results of our model show numerically that, under strong nonlinearity, surface waves, with their typical wavenumber being the resonant $k_{res}$, can be generated locally at the leading edge of the underlying, slowly varying, long-wavelength baroclinic flow. Here, the resonant $k_{res}$ satisfies the class 3 triad resonance condition among two short-mode waves and one long-mode wave in which all waves propagate in the same direction. Moreover, when the slope of the baroclinic flow is sufficiently small, only one spatially localized large-amplitude surface wave packet can be generated at the leading edge. This localized surface wave packet becomes high in amplitude and large in group velocity after the interaction with its surrounding waves. These results are qualitatively consistent with various experimental observations including resonant surface waves at the leading edge of an internal wave. Subsequently, we propose a mechanism, referred to as the modulation-resonance mechanism, underlying these surface phenomena, based on our numerical simulations. The proposed modulation-resonance mechanism combines the linear modulation, ray-based, theory for the spatiotemporal asymmetric behaviour of surface waves and the nonlinear class 3 triad resonance theory for the energy focusing of surface waves around the resonant wavenumber $k_{res}$ in Fourier space.

Shear horizontal wave propagation along a periodic metal grating surface of a magneto-electro-elastic substrate

This paper analyzes shear horizontal (SH) waves propagating in thin metal strips deposited periodically onto the surface of a magneto-electro-elastic (MEE) substrate. The MEE substrate is assumed to be a transversely isotropic crystal with 6 mm symmetry or a hexagonal (6 mm) crystal. A field analysis method, which is based on the Bloch–Floquet theory and the coupled equations of wave motion, is employed to derive the dispersion equations and wave mode shapes. Numerical examples are presented for an MEE composite (PZT4/CoFe2O4) and an aluminum (Al) strip. For comparison, different constituent ratios of PZT4/CoFe2O4 are considered. The effect of the ratios of strip height and width to grating periodicity on frequencies, phase velocities, as well as wave mode shapes is discussed in detail. The results show that there is a bandgap at the resonance condition when the grating periodicity matches the wavelength of the SH surface wave. This metal grating surface can trap SH surface waves by slowing the SH waves. The wave mode shapes indicate that the SH surface waves are trapped mainly on these metal strips. As the ratio of strip height to grating periodicity increases, the trapping effect is more pronounced and the gap becomes wider. The ratio of strip width to grating periodicity significantly affects the behavior of SH surface waves. The present results are relevant in the application of MEE surface acoustic wave resonators.

A novel method for shear horizontal surface waves in periodically layered semi-infinite structures with coating layers

The motivation of this paper is to draw attention to the research of shear horizontal (SH) surface wave dispersions in periodically layered semi-infinite structures with coating layers. Based on the properties of the symplectic matrix, a series of important conclusions regarding this subject are presented and confirmed. The propagation behaviour of SH surface waves in periodically layered semi-infinite structures can be analysed using only a single unit cell, which implies a significant reduction in the computational cost. Then based on the Wittrick-Williams (W-W) algorithm, the proposed method was extended to predict SH surface waves in periodically layered semi-infinite structures with coating layers. All eigenfreqencies can be computed by using the concept of the eigenvalue count. Two types of boundary conditions (free and clamped surfaces) are considered in this study. Finally, serval numerical examples are provided to illustrate the performance of the proposed method, which involves a comparison with previously published results and results obtained via the seeking root technique.

Analysis of surface wave behavior in corrugated piezomagnetic layer resting on inhomogeneous half-space

ABSTRACTThis paper deals with propagation of Love type waves in a Piezomagnetic layer with corrugated boundaries overlying an inhomogeneous half-space. Inhomogeneity of elastic half-space is caused due to exponential variations in elastic parameters. Dispersion relations are obtained for magnetically open and short cases. Prominent effects of inhomogeneity, layer's width and corrugation on the phase velocity of considered wave are illustrated through graphs. Some particular cases are derived and exhibited through graphs. Also the influence of undulation parameter, elastic parameter, and piezomagnetic coefficient on phase velocity of considered wave has been marked separately. The present study finds its applications in designing and optimization of Love wave sensors and Seismic Acoustic Wave (SAW) devices. Findings may also be used for analytical study of wave propagation in piezomagnetic coupled structures.

Behavior of Rayleigh surface waves in an anisotropic media lying over a prestressed orthotropic half-space

ABSTRACTThe present paper discusses the propagation of Rayleigh waves in an anisotropic layer with finite thickness lying over a prestressed orthotropic half-space. An anisotropic media and orthotropic media are supposed for the upper layer and lower half-space, respectively. Dispersion equation and displacement components are computed in a compact form considering the case that the displacement and stress are continuous at the interface and stress vanishes on a free surface. Graphs are sketched to represent the effect of density, initial stress and height of the layer on wave velocity. The graphs are also configured to exhibit the mode of propagation of Rayleigh waves. This paper is an attempt to explain the nature of Rayleigh waves mathematically.