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.

Author: Dieter Biskamp

Publisher: Cambridge University Press

ISBN: 1139441671

Category: Science

Page:

View: 895

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.

The MHD turbulence in a partially ionized gas has been studied both analytically
and numerically (see [27, 37, 40, 84]). Lithwick and Goldreich [27] provided the
first theoretical study on the damping of MHD turbulence in a partially ionized gas
...

Author: Siyao Xu

Publisher: Springer

ISBN: 9789811375156

Category: Science

Page: 157

View: 551

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.

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

Author: Philipp Grete

Publisher:

ISBN: OCLC:972382973

Category:

Page:

View: 604

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), ...

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.

Author: John V. Shebalin

Publisher:

ISBN: NASA:31769000621113

Category:

Page: 17

View: 607

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.

[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.

Author: Andrey Beresnyak

Publisher: Walter de Gruyter GmbH & Co KG

ISBN: 9783110263282

Category: Science

Page: 286

View: 483

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.

Author: Wolfgang HillebrandtPublish On: 2008-11-20

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
...

Author: Wolfgang Hillebrandt

Publisher: Springer Science & Business Media

ISBN: 354078960X

Category: Science

Page: 340

View: 802

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.

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.

Author: Thierry Passot

Publisher: Springer

ISBN: 9783540470380

Category: Science

Page: 385

View: 137

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.

In this thesis we developed a Fourier pseudo-spectral code coupled with the volume penalization for the simulation of turbulent MHD flows with non-periodic boundary conditions.

Author: Salah Neffaa

Publisher:

ISBN: OCLC:1175658909

Category:

Page: 139

View: 289

In this thesis we developed a Fourier pseudo-spectral code coupled with the volume penalization for the simulation of turbulent MHD flows with non-periodic boundary conditions. This method was validated with classical and academic test-cases. Then we studied the influence of the confinement with walls in a 2D configuration for decaying MHD and we found four decaying regimes which depend on the initial conditions. We also discussed the phenomenon of spontaneous rotation, or spin-up, in 2D non-axisymmetric geometries, originally discovered in hydrodynamic flows. We showed the influence of the Reynolds number and the magnetic pressure on this phenomenon. Finally, simulations of MHD flows in wall bounded three-dimensional domains were addressed. The first results concerning the simulation of decaying MHD turbulence in a cylinder imposing Dirichlet boundary conditions for both the velocity and the magnetic field showed the validity of the code and suggest good prospects for developing more physically justified boundary conditions for the magnetic field.

Author: National Aeronautics and Space Administration (NASA)Publish On: 2018-08-16

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.

Author: National Aeronautics and Space Administration (NASA)

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...

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
...

Author: Jackson R. Herring

Publisher: World Scientific

ISBN: 9971508273

Category: Science

Page: 371

View: 899

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.

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 ...

Author: J. M. L. M. Palma

Publisher: Springer Science & Business Media

ISBN: 3540726047

Category: Technology & Engineering

Page: 790

View: 289

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.

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.

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
...

Author: Yukio Kaneda

Publisher: Springer Science & Business Media

ISBN: 1402064721

Category: Science

Page: 450

View: 602

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.

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 ...

Author: Edith Falgarone

Publisher: Springer

ISBN: 9783540362388

Category: Science

Page: 468

View: 574

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.

TUrbulence modeling encounters mixed evaluation concerning its impor tance.

Author: A. Yoshizawa

Publisher: Springer Science & Business Media

ISBN: 9789401718103

Category: Science

Page: 416

View: 899

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.