Physica D: Nonlinear Phenomena最新文献_第3页

On spectral scaling laws for averaged turbulence on the sphere 球上平均湍流的谱标度规律

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-06-25 DOI: 10.1016/j.physd.2025.134808

Sagy Ephrati, Erik Jansson, Klas Modin

{"title":"On spectral scaling laws for averaged turbulence on the sphere","authors":"Sagy Ephrati, Erik Jansson, Klas Modin","doi":"10.1016/j.physd.2025.134808","DOIUrl":"10.1016/j.physd.2025.134808","url":null,"abstract":"<div><div>Spectral analysis for a class of Lagrangian-averaged Navier–Stokes (LANS) equations on the sphere is carried out. The equations arise from the Navier–Stokes equations by applying a Helmholtz filter of width <span><math><mi>α</mi></math></span> to the advecting velocity <span><math><mi>β</mi></math></span> times, extending previous results on the Navier–Stokes-<span><math><mi>α</mi></math></span> model and enabling a precise selection of the smallest length scale in the flow. Power laws for the energy spectrum are derived and indicate a <span><math><mi>β</mi></math></span>-dependent scaling at wave numbers <span><math><mi>l</mi></math></span> with <span><math><mrow><mi>α</mi><mi>l</mi><mo>≫</mo><mn>1</mn></mrow></math></span>. The energy and enstrophy transfer rates distinctly depend on the averaging, allowing control over the energy flux and the enstrophy flux separately through the choice of averaging operator. A necessary condition on the averaging operator is derived for the existence of the inverse cascade in two-dimensional turbulence. Numerical experiments with a structure-preserving integrator based on Zeitlin’s self-consistent truncation for hydrodynamics confirm the expected energy spectrum scalings and the robustness of the double cascade under choices of the averaging operator. The derived results have potential applications in reduced-complexity numerical simulations of geophysical flows on spherical domains.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134808"},"PeriodicalIF":2.7,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Transport enhancement and entropic stochastic resonance of Brownian particles in symmetric deformable channels 布朗粒子在对称可变形通道中的输运增强和熵随机共振

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-06-25 DOI: 10.1016/j.physd.2025.134739

N.A. Donfack Tsagni, G. Djuidjé Kenmoé

{"title":"Transport enhancement and entropic stochastic resonance of Brownian particles in symmetric deformable channels","authors":"N.A. Donfack Tsagni, G. Djuidjé Kenmoé","doi":"10.1016/j.physd.2025.134739","DOIUrl":"10.1016/j.physd.2025.134739","url":null,"abstract":"<div><div>We investigated in this work the transport enhancement and entropic stochastic resonance of Brownian particles in symmetric, corrugated, deformable channels. The diverse geometries of our channel, shown by the widening or narrowing of the potential wells and barriers, significantly affect the dynamics of Brownian particles when mass is included. We used the boundary reflection condition to retain the particles inside the channel. We have shown that under suitable parameter conditions in our systems, the channel’s symmetry can be observed in results such as the evolution of the channel’s potential barrier in relation to the biharmonic force exerted on the particles, as well as the mean first passage time and spectral amplification where entropic stochastic resonance occurs. With the rise in noise intensity, spectral amplification exhibits non-monotonic behavior, indicating the occurrence of entropic stochastic resonance. By modulating the amplitudes of the harmonics <span><math><msub><mrow><mi>A</mi></mrow><mrow><mn>0</mn></mrow></msub></math></span>, the frequency of the driving biharmonic signal <span><math><mi>ω</mi></math></span>, the scale ratio of the second harmonic <span><math><mi>ϵ</mi></math></span>, the phase lag of the two signals <span><math><mi>ϕ</mi></math></span>, and the configuration of the deformable channel, we can discern a reverse average velocity and an optimization of effective diffusion for particular particle masses. It is essential to emphasize that particle transport via channels encompasses a diverse array of processes, including osmosis, ionic current through ionic channels, particle separation, and the modeling of dilute mixtures of microscopic fragments, among others.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134739"},"PeriodicalIF":2.7,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144556593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A kneading diagram of chaotic switching oscillations in a Kerr cavity with two interacting light fields 具有两个相互作用光场的克尔腔中混沌开关振荡的揉合图

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-06-25 DOI: 10.1016/j.physd.2025.134814

Rodrigues D. Dikandé Bitha , Andrus Giraldo , Neil G.R. Broderick , Bernd Krauskopf

{"title":"A kneading diagram of chaotic switching oscillations in a Kerr cavity with two interacting light fields","authors":"Rodrigues D. Dikandé Bitha , Andrus Giraldo , Neil G.R. Broderick , Bernd Krauskopf","doi":"10.1016/j.physd.2025.134814","DOIUrl":"10.1016/j.physd.2025.134814","url":null,"abstract":"<div><div>Optical systems that combine nonlinearity with coupling between various subsystems offer a flexible platform for observing a diverse range of nonlinear dynamics. Furthermore, engineering tolerances are such that the subsystems can be identical to within a fraction of the wavelength of light; hence, such coupled systems inherently have a natural symmetry that can lead to either delocalization or symmetry breaking. We consider here an optical Kerr cavity that supports two interacting electric fields, generated by two symmetric input beams. Mathematically, this system is modeled by a four-dimensional <span><math><msub><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>-equivariant vector field with the strength and detuning of the input light as control parameters. Previous research has shown that complex switching dynamics are observed both experimentally and numerically across a wide range of parameter values. Here, we show that particular switching patterns are created at specific global bifurcations through either delocalization or symmetry breaking of a chaotic attractor. We find that the system exhibits infinitely many of these global bifurcations, which are organized by <span><math><msub><mrow><mi>Z</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span>-equivariant codimension-two Belyakov transitions. We investigate these switching dynamics by means of the continuation of global bifurcations in combination with the computation of kneading invariants and Lyapunov exponents. In this way, we provide a comprehensive picture of the interplay between different switching patterns of periodic orbits and chaotic attractors.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134814"},"PeriodicalIF":2.7,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518912","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A new general coupled (1+1) dimensional long wave short wave resonance interaction system: Derivation, bright solitons, and energy sharing collisions 一种新的一般耦合（1+1）维长波短波共振相互作用系统：推导、亮孤子和能量共享碰撞

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-06-24 DOI: 10.1016/j.physd.2025.134811

G. Ajith Kumar , T. Kanna , M. Vijayajayanthi

{"title":"A new general coupled (1+1) dimensional long wave short wave resonance interaction system: Derivation, bright solitons, and energy sharing collisions","authors":"G. Ajith Kumar , T. Kanna , M. Vijayajayanthi","doi":"10.1016/j.physd.2025.134811","DOIUrl":"10.1016/j.physd.2025.134811","url":null,"abstract":"<div><div>A new solvable physical system describing nonlinear resonant interaction between two short waves and one long wave with four wave mixing (FWM) effect is derived from the three component general coupled Schrödinger system arising in nonlinear optics, by multiple scale perturbation method. Then by using the Hirota bilinearization method, bright multisoliton (say, N) solution of the general coupled long wave short wave resonance interaction system in one dimension is obtained in the Gram determinant form. The primary focus of this work is to observe the significant role of the FWM effect on the collisions between two bright solitons, three bright solitons, and the collision between a bound soliton and a standard soliton in the new general coupled (1+1) dimensional long wave short wave resonance interaction system. The system features two different energy sharing collisions in short wave components that can be inter switched by tuning the coefficient of four-wave mixing terms whereas solitons in the long wave component always undergo elastic collision accompanied by a phase shift. The presence of FWM enables the possibility of obtaining nonsingular solutions for a wider range of system parameters, for instance, even in the absence of self-phase modulation and cross-phase modulation effects. Three soliton dynamics and bound state soliton propagation are also explored.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134811"},"PeriodicalIF":2.7,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the existence of traveling wave solutions for cold plasmas 关于冷等离子体行波解的存在性

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-06-23 DOI: 10.1016/j.physd.2025.134803

Diego Alonso-Orán , Angel Durán , Rafael Granero-Belinchón

引用次数: 0

Non-binary dynamical Ising machines for combinatorial optimization 组合优化的非二元动态伊辛机

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-06-23 DOI: 10.1016/j.physd.2025.134809

Aditya Shukla, Mikhail Erementchouk, Pinaki Mazumder

{"title":"Non-binary dynamical Ising machines for combinatorial optimization","authors":"Aditya Shukla, Mikhail Erementchouk, Pinaki Mazumder","doi":"10.1016/j.physd.2025.134809","DOIUrl":"10.1016/j.physd.2025.134809","url":null,"abstract":"<div><div>Dynamical Ising machines achieve accelerated solving of complex combinatorial optimization problems by remapping the convergence to the ground state of the classical spin networks to the evolution of specially constructed continuous dynamical systems. The main adapted principle guiding the design of such systems is based on requiring that, on the one hand, the system converges to a binary state and, on the other hand, the system’s energy in such states mimics the classical Ising Hamiltonian. The emergence of binary-like states is regarded to be an indispensable feature of dynamical Ising machines as it establishes the relation between the machine’s continuous terminal state and the inherently discrete solution of a combinatorial optimization problem. This is emphasized by problems where the unknown quantities are represented by spin complexes, for example, the graph coloring problem. In such cases, an imprecise mapping of continuous states to spin configurations may lead to invalid solutions requiring intensive post-processing. In contrast to this approach, we show that there exists a class of non-binary dynamical Ising machines without the incongruity between the continuous character of the machine’s states and the discreteness of the spin states. We demonstrate this feature by applying such a machine to the problems of finding the proper graph coloring, constructing Latin squares, and solving Sudoku puzzles. Thus, we demonstrate that the information characterizing discrete states can be unambiguously presented in essentially continuous dynamical systems. This opens new opportunities for the realization of scalable electronic accelerators of combinatorial optimization.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134809"},"PeriodicalIF":2.7,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144470977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Algebro-geometric integration to the discrete Chen–Lee–Liu system 离散陈-李-刘系统的代数-几何积分

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-06-23 DOI: 10.1016/j.physd.2025.134778

Xiaoxue Xu , Decong Yi , Xing Li , Da-jun Zhang

引用次数: 0

Uniqueness of Landau–Lifschitz solution of the 2D steady Navier–Stokes equations in an infinitely long convergent channel 无限长收敛通道中二维稳定Navier-Stokes方程Landau-Lifschitz解的唯一性

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-06-21 DOI: 10.1016/j.physd.2025.134802

Jiaqi Yang

引用次数: 0

Turbulent features near the X point of a DTT-like tokamak plasma: Electro-static and electro-magnetic fluid simulations 类dtt托卡马克等离子体X点附近的湍流特征：静电和电磁流体模拟

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-06-20 DOI: 10.1016/j.physd.2025.134800

F. Cianfrani , G. Montani

{"title":"Turbulent features near the X point of a DTT-like tokamak plasma: Electro-static and electro-magnetic fluid simulations","authors":"F. Cianfrani , G. Montani","doi":"10.1016/j.physd.2025.134800","DOIUrl":"10.1016/j.physd.2025.134800","url":null,"abstract":"<div><div>The background magnetic geometry at the edge of a tokamak plasma has to be designed in order to mitigate the particle and energy looses essentially due to turbulent transport. The Divertor-Tokamak-Test (DTT) facility under construction at ENEA Frascati will test several magnetic configurations and mitigation strategies, that are usually based on the realization of nontrivial topologies in which one or more X points are present. In order to get a clear understanding of turbulent transport near one of such X points, we perform 3D fluid simulations of tokamak edge plasma for a DTT-like scenario. We will outline: (i) the resulting turbulent spectral features and their dependence on some model parameters (the background pressure gradients and diffusivity) and on the magnetic geometry through a comparative analysis with the results of the companion paper Cianfrani and Montani (2024), (ii) the connection between small scale poloidal structures and toroidal asymmetries, (iii) the formation of quiescent regions, (iv) the crucial role of radial Dirichlet boundary conditions for the excitation of zonal flows that can screen the radial component of the magnetic field, (v) the impact of magnetic fluctuations.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134800"},"PeriodicalIF":2.7,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

On the multipeakon system of a two-component Novikov equation 双分量Novikov方程的多峰系统

IF 2.7 3区数学

Physica D: Nonlinear Phenomena Pub Date : 2025-06-19 DOI: 10.1016/j.physd.2025.134781

Xiang-Ke Chang , Jacek Szmigielski

{"title":"On the multipeakon system of a two-component Novikov equation","authors":"Xiang-Ke Chang , Jacek Szmigielski","doi":"10.1016/j.physd.2025.134781","DOIUrl":"10.1016/j.physd.2025.134781","url":null,"abstract":"<div><div>The Novikov equation is a fascinating integrable modification of the Camassa–Holm equation with remarkable properties. This paper concentrates on a two-component Novikov equation featuring a non-self-adjoint 4 × 4 Lax operator. We explore the associated forward and inverse spectral maps, as well as global existence and long-time asymptotics concerning the peakon sector. On one hand, we execute an isospectral deformation to the long-time regime to compute the relevant eigenvalues using a Moser-inspired technique. To achieve this, we first demonstrate the global existence of the peakon flows, then establish a connection between the long-time asymptotics of positions and momenta and the non-zero eigenvalues. We introduce a trio of Weyl functions and show that they are matrix-valued Stieltjes transforms of discrete positive measures, again employing the deformation technique. This effectively linearizes the peakon flows on the spectral data side. Conversely, we tackle the inverse problem using Hermite–Padé approximation techniques that involve tensor products and an added symmetry condition. The thorough analysis guarantees existence and uniqueness, yielding global multipeakon formulas.</div></div>","PeriodicalId":20050,"journal":{"name":"Physica D: Nonlinear Phenomena","volume":"481 ","pages":"Article 134781"},"PeriodicalIF":2.7,"publicationDate":"2025-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572431","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0