Study on Magnetohydrodynamic Turbulence and Its Astrophysical Applications

In closing, this book demonstrates the key role of MHD turbulence in connecting diverse astrophysical processes and unraveling long-standing astrophysical problems, as foreseen by Chandrasekhar, a founder of modern astrophysics.

Study on Magnetohydrodynamic Turbulence and Its Astrophysical Applications

Author: Siyao Xu

Publisher: Springer

ISBN: 9811375151

Page: 157

View: 781

Turbulence and magnetic fields are ubiquitous in the Universe. Their importance to astronomy cannot be overestimated. The theoretical advancements in magnetohydrodynamic (MHD) turbulence achieved during the past two decades have significantly influenced many fields of astronomy. This book provides predictive theories of the magnetic field generation by turbulence and the dissipation of MHD turbulence. These fundamental non-linear problems were believed to be tractable only numerically. This book provides complete analytical descriptions in quantitative agreement with existing numerics, as well as theoretical predictions in physical regimes still unreachable by simulations, and explanations of various related observations. It also discusses and promotes the astrophysical applications of MHD turbulence theories, including (i) the particle acceleration and radiation in high-energy phenomena, e.g., Gamma-Ray Bursts, supernova remnants, cosmic rays; (ii) interstellar density fluctuations and the effect on observations, e.g., Faraday rotation, scattering measurements of Galactic and extragalactic radio sources; (iii) density and magnetic field structure in molecular clouds toward star formation. In closing, this book demonstrates the key role of MHD turbulence in connecting diverse astrophysical processes and unraveling long-standing astrophysical problems, as foreseen by Chandrasekhar, a founder of modern astrophysics.

Magnetohydrodynamic Turbulence

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.

Magnetohydrodynamic Turbulence

Author: Dieter Biskamp

Publisher: Cambridge University Press

ISBN: 9781139441674

Page:

View: 972

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.

Large Eddy Simulations of Compressible Magnetohydrodynamic Turbulence

Supersonic, magnetohydrodynamic (MHD) turbulence is thought to play an important role in many processes - especially in astrophysics, where detailed three-dimensional observations are scarce.

Large Eddy Simulations of Compressible Magnetohydrodynamic Turbulence

Author: Philipp Grete

Publisher:

ISBN:

Page:

View: 274

Supersonic, magnetohydrodynamic (MHD) turbulence is thought to play an important role in many processes - especially in astrophysics, where detailed three-dimensional observations are scarce. Simulations can partially fill this gap and help to understand these processes. However, direct simulations with realistic parameters are often not feasible. Consequently, large eddy simulations (LES) have emerged as a viable alternative. In LES the overall complexity is reduced by simulating only large and intermediate scales directly. The smallest scales, usually referred to as subgrid-scales (SGS), ...

Broken Symmetry in Ideal Magnetohydrodynamic Turbulence

The results confirm that ideal magnetohydrodynamic turbulence is non-ergodic if there is no external magnetic field present. This is due essentially to a canonical symmetry being broken in an arbitrary dynamical representation.

Broken Symmetry in Ideal Magnetohydrodynamic Turbulence

Author: John V. Shebalin

Publisher:

ISBN:

Page: 17

View: 595

A numerical study of the long-time evolution of a number of cases of inviscid, isotropic, incompressible, three-dimensional fluid and magneto-fluid turbulence has been completed. The results confirm that ideal magnetohydrodynamic turbulence is non-ergodic if there is no external magnetic field present. This is due essentially to a canonical symmetry being broken in an arbitrary dynamical representation. The broken symmetry manifests itself as a coherent structure, i.e., a non-zero time-averaged part of the turbulent magnetic field. The coherent structure is observed, in one case, to contain about eighteen percent of the total energy. Isotropic turbulence, Ideal magnetohydrodynamics, Broken symmetry.

Turbulence in Magnetohydrodynamics

[78] J. Cho, Simulations of relativistic force-free magnetohydrodynamic
turbulence, Astrophys.J. 621 (2005), 324–327. [79] J. Cho, Non-locality of
hydrodynamic and magnetohydrodynamic turbulence, Astrophys. J. 725 (2010),
1786–1791.

Turbulence in Magnetohydrodynamics

Author: Andrey Beresnyak

Publisher: Walter de Gruyter GmbH & Co KG

ISBN: 3110263289

Page: 286

View: 631

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.

Interdisciplinary Aspects of Turbulence

Bershadskii A.: Three-dimensional isotropic magnetohydrodynamic turbulence
and thermal velocity of the solar wind ions. Phys. Plasmas. 10(12), 4613–4615 (
2003) 6. Birkhoff G.D.: Proof of the ergodic theorem. Proc. Natl. Acad. Sci. USA 17
 ...

Interdisciplinary Aspects of Turbulence

Author: Wolfgang Hillebrandt

Publisher: Springer Science & Business Media

ISBN: 9783540789604

Page: 340

View: 659

Written by experts from geophysics, astrophysics and engineering, this unique book on the interdisciplinary aspects of turbulence offers recent advances in the field and covers everything from the very nature of turbulence to some practical applications.

Broken Symmetry in Ideal Magnetohydrodynamic Turbulence

The results confirm that ideal magnetohydrodynamic turbulence is non-ergodic if there is no external magnetic field present. This is due essentially to a canonical symmetry being broken in an arbitrary dynamical representation.

Broken Symmetry in Ideal Magnetohydrodynamic Turbulence

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

ISBN: 9781725194755

Page: 38

View: 668

A numerical study of the long-time evolution of a number of cases of inviscid, isotropic, incompressible, three-dimensional fluid, and magneto-fluid turbulence has been completed. The results confirm that ideal magnetohydrodynamic turbulence is non-ergodic if there is no external magnetic field present. This is due essentially to a canonical symmetry being broken in an arbitrary dynamical representation. The broken symmetry manifests itself as a coherent structure, i.e., a non-zero time-averaged part of the turbulent magnetic field. The coherent structure is observed, in one case, to contain about eighteen percent of the total energy. Shebalin, John V. Unspecified Center NASA-TM-109017, ICASE-93-49, NAS 1.15:109017, AD-A272673 RTOP 505-90-52-01...

Nonlinear MHD Waves and Turbulence

This volume, which includes expanded versions of oral contributions pre sented at this meeting, should be of interest for a large community of resear chers in space plasmas and nonlinear sciences.

Nonlinear MHD Waves and Turbulence

Author: Thierry Passot

Publisher: Springer

ISBN: 3540470387

Page: 385

View: 921

The workshop "Nonhnear MHD Waves and Turbulence" was held at the - servatoire de Nice, December 1-4, 1998 and brought together an international group of experts in plasma physics, fluid dynamics and applied mathematics. The aim of the meeting was to survey the current knowledge on two main topics: (i) propagation of plasma waves (like Alfven, whistler or ion-acoustic waves), their instabilities and the development of a nonlinear dynamics lea ding to solitonic structures, wave collapse or weak turbulence; (ii) turbulence in magnetohydrodynamic flows and its reduced description in the presence of a strong ambient magnetic fleld. As is well known, both aspects play an important role in various geophysical or astrophysical media such as the - gnetospheres of planets, the heliosphere, the solar wind, the solar corona, the interplanetary and interstellar media, etc. This volume, which includes expanded versions of oral contributions pre sented at this meeting, should be of interest for a large community of resear chers in space plasmas and nonlinear sciences. Special effort was made to put the new results into perspective and to provide a detailed literature review. A main motivation was the attempt to relate more closely the theoretical un derstanding of MHD waves and turbulence (both weak and strong) with the most recent observations in space plasmas. Some papers also bring interesting new insights into the evolution of hydrodynamic or magnetohydrodynamic structures, based on systematic asymptotic methods.

Lecture Notes on Turbulence

MAGNETOHYDRODYNAMIC TURBULENCE Preface Magnetohydrodynamic (
MHD ) turbulence is more difficult to present in lectures than fluid turbulence is ,
for several reasons : ( 1 ) less is known about it , theoretically and experimentally
 ...

Lecture Notes on Turbulence

Author: Jackson R. Herring

Publisher: World Scientific

ISBN: 9789971508272

Page: 371

View: 250

This book is a formal presentation of lectures given at the 1987 Summer School on Turbulence, held at the National Center for Atmospheric Research under the auspices of the Geophysical Turbulence Program. The lectures present in detail certain of the more challenging and interesting current turbulence research problems in engineering, meteorology, plasma physics, and mathematics. The lecturers-Uriel Frisch (Mathematics), Douglas Lilly (Meteorology), David Montgomery (Plasma Physics), and Hendrik Tennekes (Engineering) ? are distinguished for both their research contributions and their abilities to communicate these to students with enthusiasm. This book is distinguished by its simultaneous focus on the fundamentals of turbulent flows (in neutral and ionized fluids) and on a presentation of current research tools and topics in these fields.

Advances in Turbulence XI

Scaling laws, nonlocality and structure in isotropic magnetohydrodynamic
turbulence T. A. Yousef", F. Rincon' and A. A. Schekochihin'” * DAMTP, University
of Cambridge, Cambridge CB3 OWA, UK. * Department of Physics, Imperial
College ...

Advances in Turbulence XI

Author: J. M. L. M. Palma

Publisher: Springer Science & Business Media

ISBN: 9783540726043

Page: 790

View: 616

This volume comprises the communications presented at the ETC 11, the EUROMECH European Turbulence conference held in 2007 in Porto. The scientific committee has chosen the contributions out of the following topics: Acoustics of turbulent flows; Atmospheric turbulence; Control of turbulent flows; Geophysical and astrophysical turbulence; Instability and transition; Intermittency and scaling; Large eddy simulation and related techniques; MHD turbulence; Reacting and compressible turbulence; Transport and mixing; Turbulence in multiphase and non-Newtonian flows; Vortex dynamics and structure formation; Wall bounded flows.

Progress in Turbulence Research

Developed. Magnetohydrodynamic. Turbulence. Nathan Kleeorin* Ben-Gurion
University of the Negev, Beer-Sheva, Israel ... of mean magnetic force caused by
a developed small-scale magnetohydrodynamic (MHD) turbulence is considered.

Progress in Turbulence Research

Author: Herman Branover

Publisher: AIAA

ISBN: 9781600864155

Page: 348

View: 419

IUTAM Symposium on Computational Physics and New Perspectives in Turbulence

Proceedings of the IUTAM Symposium on Computational Physics and New
Perspectives in Turbulence, Nagoya University, Nagoya, Japan, September, 11-
14, 2006 Yukio Kaneda. Dynamics of the Small Scales in Magnetohydrodynamic
 ...

IUTAM Symposium on Computational Physics and New Perspectives in Turbulence

Author: Yukio Kaneda

Publisher: Springer Science & Business Media

ISBN: 9781402064722

Page: 450

View: 321

This volume contains the proceedings of the IUTAM Symposium on Computational Physics and New Perspectives in Turbulence, held at Nagoya University, Nagoya, Japan, in September 2006. With special emphasis given to fundamental aspects of the physics of turbulence, coverage includes experimental approaches to fundamental problems in turbulence, turbulence modeling and numerical methods, and geophysical and astrophysical turbulence.

Aspects of the Theory of Incompressible MHD Turbulence with Cross helicity and Applications to the Solar Wind

This is an important constraint for turbulence theories.

Aspects of the Theory of Incompressible MHD Turbulence with Cross helicity and Applications to the Solar Wind

Author:

Publisher:

ISBN:

Page:

View: 849

Solar wind observations have shown that the normalized cross-helicity?{sub c}, the ratio of the cross-helicity spectrum to the energy spectrum, is approximately constant, independent of wavenumber, throughout the inertial range. This means that the correlation between velocity and magnetic field fluctuations is the same at every scale, that the ratio of the two Elsasser energies (w/w−)2 is the same at every scale, and that the ratio of the energy cascade times of the two Elsasser energies?+/?− is the same at every scale. In the case when the magnetic Prandtl number is unity, it can be shown from the equations of incompressible MHD that if?{sub c} is a constant, then the cascade times of the two Elsasser energies are equal so that?+/?− = 1. This is an important constraint for turbulence theories. Using this result, the Goldreich and Sridhar theory and the Boldyrev theory are generalized to MHD turbulence with nonvanishing cross-helicity in such a way that the scaling laws of the original two theories are unchanged. The derivation and some of the important properties of these more general theories shall be presented. Solar wind measurements in support of these theoretical models will also be discussed. For example, new solar wind measurements of the total energy spectrum (kinetic plus magnetic) show that the power-law exponent is closer to 3/2 than 5/3, consistent with simulations of 3D incompressible MHD turbulence with a strong mean meagnetic field that show a 3/2 scaling. For highly Alfvenic, high cross-helicity solar wind turbulence, new measurements presented her show that the average spectral index is 1.540 ± 0.033.

Hydrodynamic and Magnetohydrodynamic Turbulent Flows

TUrbulence modeling encounters mixed evaluation concerning its impor tance.

Hydrodynamic and Magnetohydrodynamic Turbulent Flows

Author: A. Yoshizawa

Publisher: Springer Science & Business Media

ISBN: 9401718105

Page: 416

View: 193

TUrbulence modeling encounters mixed evaluation concerning its impor tance. In engineering flow, the Reynolds number is often very high, and the direct numerical simulation (DNS) based on the resolution of all spatial scales in a flow is beyond the capability of a computer available at present and in the foreseeable near future. The spatial scale of energetic parts of a turbulent flow is much larger than the energy dissipative counterpart, and they have large influence on the transport processes of momentum, heat, matters, etc. The primary subject of turbulence modeling is the proper es timate of these transport processes on the basis of a bold approximation to the energy-dissipation one. In the engineering community, the turbulence modeling is highly evaluated as a mathematical tool indispensable for the analysis of real-world turbulent flow. In the physics community, attention is paid to the study of small-scale components of turbulent flow linked with the energy-dissipation process, and much less interest is shown in the foregoing transport processes in real-world flow. This research tendency is closely related to the general belief that universal properties of turbulence can be found in small-scale phenomena. Such a study has really contributed much to the construction of statistical theoretical approaches to turbulence. The estrangement between the physics community and the turbulence modeling is further enhanced by the fact that the latter is founded on a weak theoretical basis, compared with the study of small-scale turbulence.

Turbulence and Magnetic Fields in Astrophysics

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 ...

Turbulence and Magnetic Fields in Astrophysics

Author: Edith Falgarone

Publisher: Springer

ISBN: 354036238X

Page: 468

View: 892

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.

Direct and Large Eddy Simulation IV

This volume contains the proceedings of the 2001 DLES4 workshop. It describes and discusses state-of-the-art modeling and simulation approaches for complex flows.

Direct and Large Eddy Simulation IV

Author: Bernard Geurts

Publisher: Springer Science & Business Media

ISBN: 9401712638

Page: 530

View: 378

This volume contains the proceedings of the 2001 DLES4 workshop. It describes and discusses state-of-the-art modeling and simulation approaches for complex flows. Fundamental turbulence and modeling issues but also elements from modern numerical analysis are at the heart of this field of interest.

Corotating Interaction Regions

London El 4NS, U.K. Received: 31 August 1998: Accepted: 4 July 1999 Abstract.
We present an overview of the properties of magnetohydrodynamic turbulence
within corotating interaction regions (CIRs) and its effects on energetic particles.

Corotating Interaction Regions

Author: A. Balogh

Publisher: Springer Science & Business Media

ISBN: 9780792360803

Page: 411

View: 450

This volume gives a comprehensive and integrated overview of current knowledge and understanding of corotating interaction regions (CIRs) in the solar wind. It is the result of a workshop at ISSI, where space scientists involved in the Ulysses, Pioneer, Voyager, IMP-8, Wind, and SOHO missions exchanged their data and interpretations with theorists in the fields of solar and heliospheric physics. The book provides a broad synthesis of current understanding of CIRs, which form at the interface between the fast solar wind originating in the northern and southern coronal holes and the slow solar wind that originates near and within coronal streamers surrounding the heliomagnetic equator. CIRs are the dominant structure in the heliosphere near and beyond Earth on the declining phase and near the minimum of the 11-year solar activity cycle. Particles energized at the shocks that bound CIRs at heliospheric distances beyond the orbit of Earth are the dominant energetic particle population observed in the outer heliosphere at these times. Papers included in this volume cover the subject of CIRs from their dissipation in the outer hemisphere, and include discussions of complexities associated with their evolution with distance from the Sun, their three-dimensional structure, and the myriad effects that CIRs have on energetic particles throughout the heliosphere. The book is intended to provide scientists active in space physics research with an up-to-date status report on current understanding of CIRs and their effects in the heliosphere, and also to serve the advanced graduate student with introductory material on this active field of research.