Download or read book Instability driven Magnetohydrodynamic Turbulence written by Justin Wiiliam Walker and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Instability-driven turbulence is ubiquitous in astrophysical and laboratory plasmas, where it is an important component to how these systems transport energy, momentum, particles, etc. This thesis is concerned with how two instabilities drive and interact with magnetohydrodynamic turbulence. The magnetorotational instability (MRI) is the best candidate for driving turbulence in well-ionized accretion disks. In this thesis, the turbulence driven by the MRI is studied with a particular focus on how it compares to strong, driven, incompressible MHD turbulence. High-resolution, high- Reynolds number setups are analyzed to determine the existence and character of an inertial range of scales where a nonlinear cascade dominates the dynamics. In contrast to previous studies, systems with an imposed magnetic field- that activate the linear MRI-provide evidence for the existence of an inertial range when one considers the dynamics perpendicular to a strong, large-scale axial magnetic field that develops in the system. The outer scale of the turbulence is determined by balance between the linear shear, present at all scales, and the turbulent shear. In the case of a system without an imposed magnetic field-where the MRI dynamo is subcritical-evidence is found for self-sustained turbulence at magnetic Prandtl number Pm = 1. Previous work was not able produce such turbulence for systems at lower Reynolds numbers. A turbulent state is found to be easier to self-sustain in these systems in high-aspect-ratio domains, with angular momentum transport also highly dependent on aspect ratio. Vertically-extended domains exhibit higher transport. Azimuthally- extended domains show increased transport until a certain aspect ratio, beyond which the transport decreases. A phenomenological explanation is proposed by which the separation of toroidal magnetic flux vertically allows for increased transport and drive of the subcritical MRI dynamo; as the toroidal dimension is extended, the tearing mode acts to break up such large scale flux, reducing transport. Additionally, two-dimensional MHD turbulence is studied in order to test the predictions of new theories that hypothesize competition between the tearing mode and turbulent fluctuations in flows with high Lundquist number. A method is introduced to simulate evolution of single, critically- balanced eddy, thereby allowing the direct investigation of this competition. Results demonstrate the disruption of the correlated eddy structure on the shorter of the [Alfven] or tearing time. Steepening of the energy spectrum is observed, while decreased alignment is not. Generally, these results support the proposed theory, with further investigation warranted.
Download or read book Magnetohydrodynamic Turbulence written by Dieter Biskamp and published by Cambridge University Press. This book was released on 2003-07-31 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an introduction to, and modern account of, magnetohydrodynamic (MHD) turbulence, an active field both in general turbulence theory and in various areas of astrophysics. The book starts by introducing the MHD equations, certain useful approximations and the transition to turbulence. The second part of the book covers incompressible MHD turbulence, the macroscopic aspects connected with the different self-organization processes, the phenomenology of the turbulence spectra, two-point closure theory, and intermittency. The third considers two-dimensional turbulence and compressible (in particular, supersonic) turbulence. Because of the similarities in the theoretical approach, these chapters start with a brief account of the corresponding methods developed in hydrodynamic turbulence. The final part of the book is devoted to astrophysical applications: turbulence in the solar wind, in accretion disks, and in the interstellar medium. This book is suitable for graduate students and researchers working in turbulence theory, plasma physics and astrophysics.
Download or read book Magnetohydrodynamic Turbulence and Angular Momentum Transport in Accretion Disks written by Martin Elias Pessah and published by . This book was released on 2007 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: It is currently believed that angular momentum transport in accretion disks is mediated by magnetohydrodynamic (MHD) turbulence driven by the magnetorotational instability (MRI). More than 15 years after its discovery, an accretion disk model that incorporates the MRI as the mechanism driving the MHD turbulence is still lacking. This dissertation constitutes the first in a series of steps towards establishing the formalism and methodology needed to move beyond the standard accretion disk model and incorporating the MRI as the mechanism enabling the accretion process. I begin by presenting a local linear stability analysis of a compressible, differentially rotating flow and addressing the evolution of the MRI beyond the weak-field limit when magnetic tension forces due to strong toroidal fields are considered. Then, I derive the first formal analytical proof showing that, during the exponential growth of the instability, the mean total stress produced by correlated MHD fluctuations is positive and leads to a net outward flux of angular momentum. I also show that some characteristics of the MHD stresses that are determined during this initial phase are roughly preserved in the turbulent saturated state observed in local numerical simulations. Motivated by these results, I present the first mean-field MHD model for angular momentum transport driven by the MRI that is able to account for a number of correlations among stresses found in local numerical simulations. I point out the relevance of a new type of correlation that couples the dynamical evolution of the Reynolds and Maxwell stresses and plays a key role in developing and sustaining the MHD turbulence. Finally, I address how the turbulent transport of angular momentum depends on the magnitude of the local shear. I show that turbulent MHD stresses in accretion disks cannot be described in terms of shear-viscosity.
Download or read book Fast Solar Wind Driven by Parametric Decay Instability and Alfv n Wave Turbulence written by Munehito Shoda and published by Springer Nature. This book was released on 2021-04-13 with total page 94 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses key theoretical aspects concerning the formation of the solar wind: the most essential building block in the heliosphere, in which planets orbit. To understand the influence of solar activity on planetary magnetospheres and atmospheres, we need to first understand the origin of the solar wind, which is still under debate. This book presents the outcomes of state-of-the-art numerical simulations of solar wind acceleration, including the first three-dimensional simulation of the turbulence-driven solar wind model. One of the book’s goals is to include compressional effects in the dynamics of solar wind turbulence; accordingly, it discusses parametric decay instability in detail. Several key aspects that are relevant to the Parker Solar Probe observations are also discussed. Given its scope, the book plays a key role in bridging the gap between the theory of magnetohydrodynamic turbulence and current/future in-situ observations of the solar wind. This book is based on the Ph.D. thesis by the author, which won the 2019 International Astronomical Union Division E Ph.D. prize.
Download or read book Hydrodynamic Instabilities and Turbulence written by Ye Zhou and published by Cambridge University Press. This book was released on 2024-05-31 with total page 611 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first comprehensive reference guide to turbulent mixing driven by Rayleigh-Taylor, Richtmyer-Meshkov and Kelvin-Helmholtz instabilities.
Download or read book Turbulence in Magnetohydrodynamics written by Andrey Beresnyak and published by Walter de Gruyter GmbH & Co KG. This book was released on 2019-07-08 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetohydrodynamics describes dynamics in electrically conductive fluids. These occur in our environment as well as in our atmosphere and magnetosphere, and play a role in the sun's interaction with our planet. In most cases these phenomena involve turbulences, and thus are very challenging to understand and calculate. A sound knowledge is needed to tackle these problems. This work gives the basic information on turbulence in nature, comtaining the needed equations, notions and numerical simulations. The current state of our knowledge and future implications of MHD turbulence are outlined systematically. It is indispensable for all scientists engaged in research of our atmosphere and in space science.
Download or read book Turbulence written by Peter Davidson and published by Oxford University Press, USA. This book was released on 2015 with total page 647 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an advanced textbook on the subject of turbulence, and is suitable for engineers, physical scientists and applied mathematicians. The aim of the book is to bridge the gap between the elementary accounts of turbulence found in undergraduate texts, and the more rigorous monographs on the subject. Throughout, the book combines the maximum of physical insight with the minimum of mathematical detail. Chapters 1 to 5 may be appropriate as background material for an advanced undergraduate or introductory postgraduate course on turbulence, while chapters 6 to 10 may be suitable as background material for an advanced postgraduate course on turbulence, or act as a reference source for professional researchers. This second edition covers a decade of advancement in the field, streamlining the original content while updating the sections where the subject has moved on. The expanded content includes large-scale dynamics, stratified & rotating turbulence, the increased power of direct numerical simulation, two-dimensional turbulence, Magnetohydrodynamics, and turbulence in the core of the Earth
Download or read book Control of Turbulent and Magnetohydrodynamic Channel Flows written by Rafael Vazquez and published by Springer Science & Business Media. This book was released on 2007-10-06 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph presents new constructive design methods for boundary stabilization and boundary estimation for several classes of benchmark problems in flow control, with potential applications to turbulence control, weather forecasting, and plasma control. One of the main features of the book is a unique "backstepping" approach to parabolic partial differential equations, which yields not only the stabilization of the flow, but also the explicit solvability of the closed-loop system. The work is an excellent reference for a broad, interdisciplinary engineering and mathematics audience: control theorists, fluid mechanicists, mechanical engineers, aerospace engineers, chemical engineers, electrical engineers, applied mathematicians, as well as research and graduate students in these fields.
Download or read book Turbulence and Magnetic Fields in Astrophysics written by Edith Falgarone and published by Springer Science & Business Media. This book was released on 2003-03-11 with total page 484 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book contains review articles of most of the topics addressed at the conf- ence on Simulations of Magnetohydrodynamic turbulence in astrophysics: recent achievements and perspectives which took place from July 2 to 6, 2001 at the Institut Henri Poincar ́e in Paris. We made the choice to publish these lectures in a tutorial form so that they can be read by a broad audience. As a result, this book does not give an exhaustive view of all the subjects addressed during the conference. The main objective of this workshop which gathered about 90 scientists from di?erent ?elds, was to present and confront recent results on the topic of t- bulence in magnetized astrophysical environments. A second objective was to discuss the latest generation of numerical codes, such as those using adaptive mesh re?nement (AMR) techniques. During a plenary discussion at the end of the workshop discussions were held on several topics, often at the heart of vivid controversies. Topics included the timescale for the dissipation of magneto-hydrodynamical (MHD) turbulence, the role of boundary conditions, the characteristics of imbalanced turbulence, the validity of the polytropic approach to Alfv ́en waves support within interst- lar clouds, the source of turbulence inside clouds devoid of stellar activity, the timescale for star formation, the Alfv ́en Mach number of interstellar gas motions, the formation process for helical ?elds in the interstellar medium. The impact of small upon large scales was also discussed.
Download or read book Magnetohydrodynamic Turbulence written by D. Biskamp and published by . This book was released on 2003 with total page 297 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents an introduction to, and state-of-the-art account of, magnetohydrodynamic (MHD) turbulence. Applications to three topics from astrophysics are considered: the solar wind, accretion disks, and the interstellar medium. Suitable for graduate students and researchers working in turbulence theory, plasma physics and astrophysics.
Download or read book The Suppression of Turbulence in Combustion driven Magnetohydrodynamic Flows written by John Charles Reis and published by . This book was released on 1982 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Direct Numerical Simulations of Variable density Instability Driven Turbulence written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Of Buoyant Flows From Instabilities To Turbulence written by Mahendra Kumar Verma and published by World Scientific. This book was released on 2018-05-30 with total page 352 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gravity pervades the whole universe; hence buoyancy drives fluids everywhere including those in the atmospheres and interiors of planets and stars. Prime examples of such flows are mantle convection, atmospheric flows, solar convection, dynamo process, heat exchangers, airships and hot air balloons. In this book we present fundamentals and applications of thermal convection and stratified flows.Buoyancy brings in extremely rich phenomena including waves and instabilities, patterns, chaos, and turbulence. In this book we present these topics in a systematic manner. First we present a unified treatment of linear theory that yields waves and thermal instability for stably and unstably-stratified flows respectively. We extend this analysis to include rotation and magnetic field. We also describe nonlinear saturation and pattern formation in Rayleigh-Bénard convection.The second half of the book is dedicated to buoyancy-driven turbulence, both in stably-stratified flow and in thermal convection. We describe the spectral theory including energy flux and show that the thermally-driven turbulence is similar to hydrodynamic turbulence. We also describe large-scale quantities like Reynolds and Nusselt numbers, flow anisotropy, and the dynamics of flow structures, namely flow reversals. Thus, this book presents all the major aspects of the buoyancy-driven flows in a coherent manner that would appeal to advanced graduate students and researchers.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence and Instabilities in Magnetised Plasmas written by Bruce Scott and published by Iop Plasma Physics. This book was released on 2021-11-18 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ever since the first observations of turbulent fluctuations in laboratory plasma experiments in the years around 1980, turbulence in magnetised plasmas has been a subject of vigorous interest in the field of plasma physics and magnetic confinement. The second of a two-volume set, this book begins with a review of the concepts behind magnetised plasma turbulence as covered in Volume One. After covering the effects of temperature dynamics, especially heat flux inertia, the rest of the first half reviews classical field theory in the necessary language, then builds the gyrokinetic and gyrofluid theory in a systematic and self-consistent manner, with special emphasis on energetic consistency. Gyrofluid turbulence in various flavours in a magnetised plasma is then covered, with control cases and energetic analysis. Familiar magnetohydrodynamic instabilities are reproduced in gyrofluid language, and then turbulence in a flow layer, current channel, pressure layer, or all three, is covered. A reprise of the theory in terms of a gauge transform with functional Lie-Poisson bracket structure closes the volume. Key Features Written by a world-leading expert in magnetised plasma turbulence Fills a long-standing gap in the plasma physics literature First unified book on gyrokinetic and gyrofluid theory and turbulence Includes complete derivations of the fundamental concepts
Download or read book An Introduction to Magnetohydrodynamics written by P. A. Davidson and published by Cambridge University Press. This book was released on 2001-03-05 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is an introductory text on magnetohydrodynamics (MHD) - the study of the interaction of magnetic fields and conducting fluids.
Download or read book Ideal MHD written by Jeffrey P. Freidberg and published by Cambridge University Press. This book was released on 2014-06-26 with total page 743 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprehensive, self-contained, and clearly written, this book describes the macroscopic equilibrium and stability of high temperature plasmas.