Wave Turbulence Under Parametric Excitation

WAVE TURBULENCE is a state of a system of many simultaneously excited and interacting waves characterized by an energy distribution which is not in any sense close to thermodynamic equilibrium. Such situations in a choppy sea, in a hot plasma, in dielectrics under arise, for example, a powerful laser beam, in magnets placed in a strong microwave field, etc. Among the great variety of physical situations in which wave turbulence arises, it is possible to select two large limiting groups which allow a detailed analysis. The first is fully developed wave turbulence arising when energy pumping and dissipation have essentially different space scales. In this case there is a wide power spectrum of turbulence. This type of turbulence is described in detail e. g. in Zakharov et al. 1 In the second limiting case the scales in which energy pumping and dissipation occur are the same. As a rule, in this case a narrow, almost singular spectrum of turbulence appears which is concentrated near surfaces, curves or even points in k-space. One of the most important, widely investigated and instructive examples of this kind of turbulence is parametric wave turbulence appearing as a result of the evolution of a parametric instability of waves in media under strong external periodic modulation (laser beam, microwave electromagnetic field, etc. ). The present book deals with parametric wave turbulence.

This much-needed book addresses the concepts, models, experiments and applications of magnons and spin wave in magnetic devices. It fills the gap in the current literature by providing the theoretical and technological framework needed to develop innovative magnetic devices, such as recording devices and sensors. Starting with a historical review of developments in the magnon concept, and including original experimental results, the author presents methods of magnon excitation, and several basic models to describe magnon gas. He includes experiments on Bose-Einstein condensation of non-equilibrium magnons, as well as various applications of a magnon approach.

MODERN FERRITES, Volume 1 A robust exploration of the basic principles of ferrimagnetics and their applications In Modern Ferrites Volume 1: Basic Principles, Processing and Properties, renowned researcher and educator Vincent G. Harris delivers a comprehensive overview of the basic principles and ferrimagnetic phenomena of modern ferrite materials. Volume 1 explores the fundamental properties of ferrite systems, including their structure, chemistry, and magnetism; the latest in processing methodologies; and the unique properties that result. The authors explore the processing, structure, and property relationships in ferrites as nanoparticles, thin and thick films, compacts, and crystals and how these relationships are key to realizing practical device applications laying the foundation for next generation technologies. This volume also includes: Comprehensive investigation of the historical and scientific significance of ferrites upon ancient and modern societies; Neel’s expanded theory of molecular field magnetism applied to ferrimagnetic oxides together with theoretic advances in density functional theory; Nonlinear excitations in ferrite systems and their potential for device technologies; Practical discussions of nanoparticle, thin, and thick film growth techniques; Ferrite-based electronic band-gap heterostructures and metamaterials. Perfect for RF engineers and magnetitians working in the field of RF electronics, radar, communications, and spintronics as well as other emerging technologies. Modern Ferrites will earn a place on the bookshelves of engineers and scientists interested in the ever-expanding technologies reliant upon ferrite materials and new processing methodologies. Modern Ferrites Volume 2: Emerging Technologies and Applications is also available (ISBN: 9781394156139).

Wave Turbulence refers to the statistical theory of weakly nonlinear dispersive waves. There is a wide and growing spectrum of physical applications, ranging from sea waves, to plasma waves, to superfluid turbulence, to nonlinear optics and Bose-Einstein condensates. Beyond the fundamentals the book thus also covers new developments such as the interaction of random waves with coherent structures (vortices, solitons, wave breaks), inverse cascades leading to condensation and the transitions between weak and strong turbulence, turbulence intermittency as well as finite system size effects, such as “frozen” turbulence, discrete wave resonances and avalanche-type energy cascades. This book is an outgrow of several lectures courses held by the author and, as a result, written and structured rather as a graduate text than a monograph, with many exercises and solutions offered along the way. The present compact description primarily addresses students and non-specialist researchers wishing to enter and work in this field.

By bringing together various ideas and methods for extracting the slow manifolds, the authors show that it is possible to establish a more macroscopic description in nonequilibrium systems. The book treats slowness as stability. A unifying geometrical viewpoint of the thermodynamics of slow and fast motion enables the development of reduction techniques, both analytical and numerical. Examples considered in the book range from the Boltzmann kinetic equation and hydrodynamics to the Fokker-Planck equations of polymer dynamics and models of chemical kinetics describing oxidation reactions. Special chapters are devoted to model reduction in classical statistical dynamics, natural selection, and exact solutions for slow hydrodynamic manifolds. The book will be a major reference source for both theoretical and applied model reduction. Intended primarily as a postgraduate-level text in nonequilibrium kinetics and model reduction, it will also be valuable to PhD students and researchers in applied mathematics, physics and various fields of engineering.

Microwave Physics and Techniques discusses the modelling and application of nonlinear microwave circuits and the problems of microwave electrodynamics and applications of magnetic and high Tc superconductor structures. Aspects of advanced methods for the structural investigation of materials and of MW remote sensing are also considered. The dual focus on both HTSC MW device physics and MW excitation in ferrites and magnetic films will foster the interaction of specialists in these different fields.

Since the publication of the first edition of Spin-Wave Confinement, the magnetic community’s interest in dynamic excitations in magnetic systems of reduced dimensions has been increasing. Although the concept of spin waves and their quanta (magnons) as propagating excitation of magnetic media was introduced more than 80 years ago, this field has been repeatedly bringing us fascinating new physical phenomena. The successful development of magnonics as an emerging subfield of spintronics, which considers confined spin waves as a basis for smaller, faster, more robust, and more power-efficient electronic devices, inevitably demands reduction in the sizes and dimensions of the magnetic systems being studied. The unique features of magnons, including the possibility of carrying spin information over relatively long distances, the possibility of achieving submicrometer wavelength at microwave frequencies, and controllability by electronic signal via magnetic fields, make magnonic devices distinctively suited for implementation of novel integrated electronic schemes characterized by high speed, low power consumption, and extended functionalities. Edited by S. O. Demokritov, a prominent magnonics researcher who has successfully collected the results of cutting-edge research by almost all main players in the field, this book is for everyone involved in nanotechnology, spintronics, magnonics, and nanomagnetism.

This unique handbook compiles and details cutting-edge research in nanomagnetism and its applications in spintronics, magnetoplasmonics, and nonlinear magneto-optics. Fundamental aspects of magnetism relevant to nanodevices and new spin-transfer torque random-access memory (STT-RAM), current-induced domain wall motion memory, and spin torque oscillators, as well as highly anisotropic materials and topics on magnetization damping are developed in detail in the book. New paradigms such as molecule-based magnets (MBMs), which are a promisingly adaptive class of solids poised to open new frontiers of exploration, are also covered. The relationship between magnetism and nonlinear optics and the new field of magnetoplasmonics is also developed in detail. The book also includes a thorough chapter on spin-polarized scanning tunneling microscopy (SP-STM), which enables studying magnetic phenomena on surfaces with real-space imaging and spectroscopy techniques down to the atomic level. All these topics are developed by an interdisciplinary team of leading experts in their pertinent fields. The book will certainly appeal to anyone involved in nanomagnetism and its application in spintronic nanodevices and nonlinear magneto-optics.