Download or read book Helicity of the Solar Magnetic Field written by Sanjiv Kumar Tiwari and published by LAP Lambert Academic Publishing. This book was released on 2010-08 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic helicity is a physical quantity that measures the complexity in the field lines. It is given by a volume integral over scalar product of magnetic field and its vector potential. Direct computation of magnetic helicity in the solar atmosphere is not possible in want of observations to compute the volume integral. We have clarified the physical meaning of and its relation with the magnetic helicity. An analytical bipole was generated to study the effect of polarimetric noise on the estimation of various magnetic parameters. We then examined the fine structures of sunspots in terms of local current and . The concept of signed shear angle (SSA) has been introduced. Spatially averaged SSA (SASSA) gives actual twist present in a sunspot at an observed height irrespective of force-free nature and shape of sunspots. We find that there is no net current in the sunspots even in the presence of significant twist which is consistent with fibril-bundle structure of sunspot magnetic fields. The SASSA holds promise to be very useful in predicting the severity of solar flares. A good correlation has been found among the signs of helicity at different heights in the solar atmosphere.
Download or read book Magnetic Helicity Spheromaks Solar Corona Loops And Astrophysical Jets written by Paul M Bellan and published by World Scientific. This book was released on 2018-03-12 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: Pedagogical in style, this book provides insights into plasma behavior valid over twenty orders of magnitude in both time and space. The book assumes that the reader has a basic knowledge of magnetohydrodynamics and explains topics using detailed theoretical analysis supported by discussion of relevant experiments. This comprehensive approach gives the reader an understanding of the essential theoretical ideas and their application to real situations.The book starts by explaining the topological concept of magnetic helicity and then develops a helicity-based model that predicts the ultimate state towards which magnetically-dominated plasmas evolve. The model predicts that no matter how messy or complicated the dynamics, a great range of plasma configurations always self-organize to a unique, simple final state. This self-organization, called relaxation, is a fundamental concept that unifies understanding of spheromaks, solar corona loops, interplanetary magnetic clouds, and astrophysical jets.After establishing why relaxation occurs, the book then examines how relaxation occurs. It shows that relaxation involves a sequence of complex non-equilibrium dynamics including fast self-collimated plasma jets, kink instabilities, magnetic reconnection, and phenomena outside the realm of magnetohydrodynamics.
Download or read book Magnetic Helicity at the Sun in Solar Wind and Magnetospheres written by Jörg Büchner and published by . This book was released on 2003 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mean Field Magnetohydrodynamics and Dynamo Theory written by F. Krause and published by Elsevier. This book was released on 2016-01-22 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mean-Field Magnetohydrodynamics and Dynamo Theory provides a systematic introduction to mean-field magnetohydrodynamics and the dynamo theory, along with the results achieved. Topics covered include turbulence and large-scale structures; general properties of the turbulent electromotive force; homogeneity, isotropy, and mirror symmetry of turbulent fields; and turbulent electromotive force in the case of non-vanishing mean flow. The turbulent electromotive force in the case of rotational mean motion is also considered. This book is comprised of 17 chapters and opens with an overview of the general concept of mean-field magnetohydrodynamics, followed by a discussion on the back-reaction of the magnetic field on motion; the structure of the turbulent electromotive force; homogeneous and two-scale turbulence; turbulent electromotive force in the case of rotational mean motion; and the dynamo problem of magnetohydrodynamics. The dynamo theory, which is based on mean-field magnetohydrodynamics, is explained and its applications to cosmical objects are described. The remaining chapters explore toroidal and poloidal vector fields; a simple model of an a-effect dynamo; and spherical models of turbulent dynamos as suggested by cosmical bodies. This monograph will be of interest to physicists.
Download or read book Magnetohydrodynamics of the Sun written by Eric Priest and published by Cambridge University Press. This book was released on 2014-04-07 with total page 581 pages. Available in PDF, EPUB and Kindle. Book excerpt: This advanced textbook reviews the complex interaction between the Sun's plasma atmosphere and its magnetic field.
Download or read book Self Exciting Fluid Dynamos written by Keith Moffatt and published by Cambridge University Press. This book was released on 2019-04-25 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exploring the origins and evolution of magnetic fields in planets, stars and galaxies, this book gives a basic introduction to magnetohydrodynamics and surveys the observational data, with particular focus on geomagnetism and solar magnetism. Pioneering laboratory experiments that seek to replicate particular aspects of fluid dynamo action are also described. The authors provide a complete treatment of laminar dynamo theory, and of the mean-field electrodynamics that incorporates the effects of random waves and turbulence. Both dynamo theory and its counterpart, the theory of magnetic relaxation, are covered. Topological constraints associated with conservation of magnetic helicity are thoroughly explored and major challenges are addressed in areas such as fast-dynamo theory, accretion-disc dynamo theory and the theory of magnetostrophic turbulence. The book is aimed at graduate-level students in mathematics, physics, Earth sciences and astrophysics, and will be a valuable resource for researchers at all levels.
Download or read book Magnetic Helicity in Space and Laboratory Plasmas written by Michael R. Brown and published by American Geophysical Union. This book was released on 1999-01-26 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 111. Using the concept of magnetic helicity, physicists and mathematicians describe the topology of magnetic fields: twisting, writhing, and linkage. Mathematically, helicity is related to linking integrals, which Gauss introduced in the 19th century to describe the paths of asteroids in the sky. In the late 1970s the concept proved to be critical to understand laboratory plasma experiments on magnetic reconnection, dynamos, and magnetic field relaxation. In the late 1980s it proved equally important in understanding turbulence in the solar wind and the interplanetary magnetic field. During the last five years interest in magnetic helicity has grown dramatically in solar physics, and it will continue to grow as observations of vector magnetic fields become increasingly sophisticated.
Download or read book Cosmic Magnetic Fields IAU S259 written by International Astronomical Union. Symposium and published by Cambridge University Press. This book was released on 2009-06-11 with total page 716 pages. Available in PDF, EPUB and Kindle. Book excerpt: IAU Symposium 259 presents the first interdisciplinary, comprehensive review of the role of cosmic magnetic fields, involving astronomers and physicists from across the community. Offering both theoretical and observational topics ranging from Earth's habitability to the origin of the universe, this is an invaluable summary for researchers and graduate students.
Download or read book The Role of Helicity in Magnetic Reconnection 3D Numerical Simulations written by and published by . This book was released on 1999 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: We demonstrate that conservation of global helicity plays only a minor role in determining the nature and consequences of magnetic reconnection in the solar atmosphere. First, we show that observations of the solar coronal magnetic field are in direct conflict with Taylor's theory. Next, we present results from three-dimensional MHD simulations of the shearing of bipolar and multi-polar coronal magnetic fields by photospheric footpoint motions, and discuss the implications of these results for Taylor's theory and for models of solar activity. The key conclusion of this work is that significant magnetic reconnection occurs only at very specific locations and, hence the Sun's magnetic field cannot relax completely down to the minimum energy state predicted by conservation of global helicity.
Download or read book Astrophysical Magnetic Fields written by Anvar Shukurov and published by Cambridge University Press. This book was released on 2021-12-16 with total page 641 pages. Available in PDF, EPUB and Kindle. Book excerpt: This self-contained introduction to astrophysical magnetic fields provides a comprehensive review of the current state of the field and a critical discussion of the latest research. Its emphasis on results that are likely to form the basis for future progress benefits a broad audience of advanced students and active researchers.
Download or read book Helicities in Geophysics Astrophysics and Beyond written by Kirill Kuzanyan and published by John Wiley & Sons. This book was released on 2023-12-12 with total page 275 pages. Available in PDF, EPUB and Kindle. Book excerpt: Helicities in Geophysics, Astrophysics, and Beyond Helicities play essential roles in numerous geophysical, astrophysical, and magnetohydrodynamic phenomena, thus are studied from various disciplinary viewpoints. Helicities in Geophysics, Astrophysics, and Beyond draws together experts from different research fields to present an interdisciplinary and integrated approach to helicity studies. This synthesis advances understanding of the fundamental physical processes underlying various helicity-related phenomena. Volume highlights include: Concise introduction to fundamental properties of helicities Recent developments and achievements in helicity studies Perspectives from different fields including geophysics, space physics, solar physics, plasma physics, atmospheric and nonlinear sciences A cohesive mathematical, physical, observational, experimental, and numerical strategy for helicity studies A synthesized framework for the application of helicity to real-world problems The American Geophysical Union promotes discovery in Earth and space science for the benefit of humanity. Its publications disseminate scientific knowledge and provide resources for researchers, students, and professionals.
Download or read book Turbulent Transport In Magnetized Plasmas Second Edition written by C Wendell Horton, Jr and published by #N/A. This book was released on 2017-07-21 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: For a few seconds with large machines, scientists and engineers have now created the fusion power of the stars in the laboratory and at the same time find the rich range of complex turbulent electromagnetic waves that transport the plasma confinement systems. The turbulent transport mechanisms created in the laboratory are explained in detail in the second edition of 'Turbulent Transport in Magnetized Plasmas' by Professor Horton.The principles and properties of the major plasma confinement machines are explored with basic physics to the extent currently understood. For the observational laws that are not understood — the empirical confinement laws — offering challenges to the next generation of plasma students and researchers — are explained in detail. An example, is the confinement regime — called the 'I-mode' — currently a hot topic — is explored.Numerous important problems and puzzles for the next generation of plasma scientists are explained. There is growing demand for new simulation codes utilizing the massively parallel computers with MPI and GPU methods. When the 20 billion dollar ITER machine is tested in the 2020ies, new theories and faster/smarter computer simulations running in near real-time control systems will be used to control the burning hydrogen plasmas.
Download or read book Spheromaks A Practical Application Of Magnetohydrodynamic Dynamos And Plasma Self organization written by Paul M Bellan and published by World Scientific. This book was released on 2000-01-22 with total page 357 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spheromaks are easily formed, self-organized magnetized plasma configurations that have intrigued plasma physicists for over two decades. Sometimes called magnetic vortices, magnetic smoke rings, or plasmoids, spheromaks first attracted attention as a possible controlled thermonuclear plasma confinement scheme, but are now known to have many other applications.This book begins with a review of the basic concepts of magnetohydrodynamics and toroidal magnetic configurations, then provides a detailed exposition of the 3D topological concepts underlying spheromak physics, namely magnetic helicity, Taylor relaxation, force-free equilibria, and tilt stability. It then examines spheromak formation techniques, driven and isolated configurations, dynamo concepts, practical experimental issues, diagnostics, and a number of applications. The book concludes by showing how spheromak ideas are closely related to the physics of solar prominences and interplanetary magnetic clouds./a
Download or read book Solar Prominences written by Jean-Claude Vial and published by Springer. This book was released on 2014-11-24 with total page 490 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the latest research results on solar prominences, including new developments on e.g. chirality, fine structure, magnetism, diagnostic tools and relevant solar plasma physics. In 1875 solar prominences, as seen out of the solar limb, were described by P.A. Secchi in his book Le Soleil as "gigantic pink or peach-flower coloured flames". The development of spectroscopy, coronagraphy and polarimetry brought tremendous observational advances in the twentieth century. The authors present and discuss exciting new challenges (resulting from observations made by space and ground-based telescopes in the 1990s and the first decade of the 21st century) concerning the diagnostics of prominences, their formation, their life time and their eruption along with their impact in the heliosphere (including the Earth). The book starts with a general introduction of the prominence “object” with some historical background on observations and instrumentation. In the next chapter, the various forms of prominences are described with a thorough attempt of classification. Their thermodynamic (and velocity) properties are then derived with emphasis on the methods (and their limits) used. This goes from the simplest optically thin case to the heavy radiative treatment of plasmas out of local thermodynamic equilibrium. The following chapters are devoted to the magnetic field measurements and indirect derivation. A new branch of diagnostic tools, the seismology, is presented along with some MHD basics. This allows to better understand the propagation of waves, the energy and force equilibria. Both small-scale and large-scale studies and their relationship are presented. The importance of the newly discovered cavities is stressed in the context of prominence destabilization. The issues of prominence formation and eruption, their connection with flares and Coronal Mass Ejections and their impact on the Earth are addressed on the basis of the latest results. Finally, an exciting new area of research is unveiled with the newly discovered evidence of similar manifestations in the Universe and their possible impact on the habitability of exoplanets. References to the basic physics (where necessary) are provided and the proposed web sites addresses will allow the reader to load exciting movies. The book is aimed at advanced students in astrophysics, post-graduates, solar physicists and more generally astrophysicists. Amateurs will enjoy the many new images which go with the text.
Download or read book Magnetic Helicity in the Solar Corona written by Mitchell Anthony Berger and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar Magnetism written by Hongqi Zhang and published by Springer Nature. This book was released on 2023-08-14 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights fundamentals and advances in the theories and observations of solar magnetic fields. Solar magnetism is an important part of solar physics and space weather research. It covers the formation, development, and relaxation of the magnetic fields in the solar eruptive process. The book discusses topics ranging from measurement facilities for solar observations to the evolution of solar magnetic fields, the storage of magnetic energy, and the magnetic helicity in the solar atmosphere and its relation with solar cycles. The book also presents recent advances in measurements and observations of solar magnetic shear, currents, magnetic helicity, and solar cycles. The book intends for astronomy-majored students and researchers interested in solar magnetism and its role in astrophysics.
Download or read book Introduction to Turbulent Transport of Particles Temperature and Magnetic Fields written by Igor Rogachevskii and published by Cambridge University Press. This book was released on 2021-08-05 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulence and the associated turbulent transport of scalar and vector fields is a classical physics problem that has dazzled scientists for over a century, yet many fundamental questions remain. Igor Rogachevskii, in this concise book, systematically applies various analytical methods to the turbulent transfer of temperature, particles and magnetic field. Introducing key concepts in turbulent transport including essential physics principles and statistical tools, this interdisciplinary book is suitable for a range of readers such as theoretical physicists, astrophysicists, geophysicists, plasma physicists, and researchers in fluid mechanics and related topics in engineering. With an overview to various analytical methods such as mean-field approach, dimensional analysis, multi-scale approach, quasi-linear approach, spectral tau approach, path-integral approach and analysis based on budget equations, it is also an accessible reference tool for advanced graduates, PhD students and researchers.
