Download or read book Investigation Into the Influence of Magnetic Field Structure on the Dynamical and Spatial Properties of Plasma Edge Turbulence in the Stellarator TJ K written by Stephen Garland and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Turbulence in Space Plasmas written by Loukas Vlahos and published by Springer. This book was released on 2009-06-12 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the years, many leading European graduate schools in the field of astrophysical and space plasmas have operated within the framework of the research network, "Theory, Observations, and Simulations in Turbulence in Space Plasmas." This text is a set of lectures and tutorial reviews culled from the relevant work of all those schools. It emphasizes applications on solar coronae, solar flares, and the solar wind. In bridging the gap between standard textbook material and state-of-the-art research, this text offers a broad flavor to postgraduate and postdoctoral students just coming to the field. And because of its unique mix, it will also be useful to lecturers looking for advanced teaching material for their seminars and courses.
Download or read book Magnetic Stochasticity in Magnetically Confined Fusion Plasmas written by Sadrilla Abdullaev and published by Springer. This book was released on 2016-08-27 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first book to systematically consider the modern aspects of chaotic dynamics of magnetic field lines and charged particles in magnetically confined fusion plasmas. The analytical models describing the generic features of equilibrium magnetic fields and magnetic perturbations in modern fusion devices are presented. It describes mathematical and physical aspects of onset of chaos, generic properties of the structure of stochastic magnetic fields, transport of charged particles in tokamaks induced by magnetic perturbations, new aspects of particle turbulent transport, etc. The presentation is based on the classical and new unique mathematical tools of Hamiltonian dynamics, like the action--angle formalism, classical perturbation theory, canonical transformations of variables, symplectic mappings, the Poincaré-Melnikov integrals. They are extensively used for analytical studies as well as for numerical simulations of magnetic field lines, particle dynamics, their spatial structures and statistical properties. The numerous references to articles on the latest development in the area are provided. The book is intended for graduate students and researchers who interested in the modern problems of magnetic stochasticity in magnetically confined fusion plasmas. It is also useful for physicists and mathematicians interested in new methods of Hamiltonian dynamics and their applications.
Download or read book Investigation of the Dynamics of Coherent Structure Bbf and Intermittent Turbulence in Earth s Magnetotail written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: We have achieved all the goals stated in our grant proposal. Specifically, these include: 1. The understanding of the complexity induced nonlinear spatiotemporal coherent structures and the coexisting propagating modes. 2. The understanding of the intermittent turbulence and energization process of the observed Bursty Bulk Flows (BBF's) in the Earth s magnetotail. 3. The development of "anisotropic three-dimensional complexity" in the plasma sheet due to localized merging and interactions of the magnetic coherent structures. 4. The study of fluctuation-induced nonlinear instabilities and their role in the reconfiguration of magnetic topologies in the magnetotail based on the concepts of the dynamic renormalization group. 5. The acceleration of ions due to the intermittent turbulence of propagating and nonpropagating fluctuations. In the following, we include lists of our published papers, invited talks, and professional activities. A detailed description of our accomplished research results is given..Chang, TomGoddard Space Flight CenterSPACE PLASMAS; NONLINEARITY; MAGNETIC FIELD CONFIGURATIONS; TURBULENCE; GEOMAGNETIC TAIL; IONS; PLASMA LAYERS; RENORMALIZATION GROUP METHODS
Download or read book Analytical and Numerical Investigation of Energetic Particles Interacting with Turbulent Magnetic Fields written by Martin H. Heusen and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fundamental problem in astrophysics is the interaction between space plasmas and energetic particles. Plasmas form the vast majority of space and can be found in any astrophysical environment, from the plasma of the solar wind to the interstellar medium for example. When plasmas stream through space, they give rise to turbulent magnetic fields. In addition, space is populated by energetic particles whose origins could be interplanetary, such as solar energetic particles generated by explosions on the surface of the Sun, or Galactic, such as cosmic rays generated by supernova remnants. As these particles propagate through interplanetary or interstellar space, they experience scattering due to magnetic turbulence. Describing these scattering effects, through the calculation of diffusion coefficients, is crucial to understanding several important processes in astrophysics. Such processes include particle acceleration at interplanetary shocks, solar modulation and space weather studies, and the motion of cosmic rays through galaxies. A test-particle code is developed to simulate the interaction of charged particles with turbulent magnetic fields. Diffusion coefficients along and across the mean magnetic field are calculated and compared with analytical theories and space mission measurements. Turbulence models with reduced dimensionality and full three-dimensional corresponding to different space settings are considered, including reproducing the magnetic turbulence in the solar wind and the interstellar medium. Wave propagation, dynamical effects, and unique turbulence setups such as noisy hydrodynamic models are also considered. We show that the influence of turbulence properties and various space regimes on transport parameters is minor and not as strong as originally thought. This points toward a universal transport behaviour of charged particles which motivates the employment of a comprehensive diffusion formula for different space settings. In addition, we were able for the first time to accurately describe the interaction between Galactic cosmic rays and dynamical solar wind turbulence to reproduce observational results of mean free paths. The validity of certain asymptotic limits for the parallel and perpendicular diffusion coefficients are examined. It is shown that only two parameters control those limits, namely the fundamental length scale of magnetic turbulence and the ratio of turbulence strength to the mean field.
Download or read book Dynamics of Magnetically Trapped Particles written by Juan G. Roederer and published by Springer Science & Business Media. This book was released on 2013-12-13 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a new edition of Roederer’s classic Dynamics of Geomagnetically Trapped Radiation, updated and considerably expanded. The main objective is to describe the dynamic properties of magnetically trapped particles in planetary radiation belts and plasmas and explain the physical processes involved from the theoretical point of view. The approach is to examine in detail the orbital and adiabatic motion of individual particles in typical configurations of magnetic and electric fields in the magnetosphere and, from there, derive basic features of the particles’ collective “macroscopic” behavior in general planetary environments. Emphasis is not on the “what” but on the “why” of particle phenomena in near-earth space, providing a solid and clear understanding of the principal basic physical mechanisms and dynamic processes involved. The book will also serve as an introduction to general space plasma physics, with abundant basic examples to illustrate and explain the physical origin of different types of plasma current systems and their self-organizing character via the magnetic field. The ultimate aim is to help both graduate students and interested scientists to successfully face the theoretical and experimental challenges lying ahead in space physics in view of recent and upcoming satellite missions and an expected wealth of data on radiation belts and plasmas.
Download or read book Study of the Magnetic Field Structure of the TOR 2 Stellarator written by M. A. Ivanovskii and published by . This book was released on 1970 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of the Equilibrium Magnetic Field on Plasma Edge Fluctuations written by and published by . This book was released on 1990 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: The magnetic field structure reflected in the safety factor (q) profile can play an important role in defining some of the basic structures of the magnetohydrodynamic (MHD) turbulence: it plays a role in the generation of spatial structures in the initial nonlinear phase, and it gives a radial dependence to the spectral average of the square of the poloidal mode number, {l angle}m2{r angle}12, that can modify the explicit dependences of an analytically derived expression for turbulence-induced anomalous losses. 12 refs., 4 figs.
Download or read book Stellarator and Heliotron Devices written by Masahiro Wakatani and published by Oxford University Press, USA. This book was released on 1998 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph describes plasma physics for magnetic confinement of high temperature plasmas in nonaxisymmetric toroidal magnetic fields or stellarators. The techniques are aimed at controlling nuclear fusion for continuous energy production. While the focus is on the nonaxisymmetric toroidal field, or heliotron, developed at Kyoto University, the physics applies equally to other stellarators and axisymmetric tokamaks. The author covers all aspects of magnetic confinement, formation of magnetic surfaces, magnetohydrodynamic equilibrium and stability, single charged particle confinement, neoclassical transport and plasma heating. He also reviews recent experiments and the prospects for the next generation of devices.
Download or read book Influence of Magnetic Field Structure on the Conduction Cooling of Flare Loops written by Stanford University. Institute for Plasma Research and published by . This book was released on 1976 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: A simple model facilitates calculation of the influence of magnetic field configuration on the conduction cooling rate of a hot post-flare coronal plasma. The magnetic field is taken to be that produced by a line dipole or point dipole at an arbitrary depth below the chromosphere. For the high temperatures (T> or = 10 to the 7th power K) produced by flares, the plasma may remain static and isobaric. The influence of the field is such as to increase the heat flux (per unit area) into the chromosphere, but to decrease the total conduction cooling of the flare plasma. This leads to a significant enhancement of the total energy radiated by the flare plasma. (Author).
Download or read book Investigation of the Structure of Magnetic Surfaces in Stellarators with L written by M. S. Berezhetskii and published by . This book was released on 1965 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scaling Laws in Magnetized Plasma Turbulence written by and published by . This book was released on 2015 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interactions of plasma motion with magnetic fields occur in nature and in the laboratory in an impressively broad range of scales, from megaparsecs in astrophysical systems to centimeters in fusion devices. The fact that such an enormous array of phenomena can be effectively studied lies in the existence of fundamental scaling laws in plasma turbulence, which allow one to scale the results of analytic and numerical modeling to the sized of galaxies, velocities of supernovae explosions, or magnetic fields in fusion devices. Magnetohydrodynamics (MHD) provides the simplest framework for describing magnetic plasma turbulence. Recently, a number of new features of MHD turbulence have been discovered and an impressive array of thought-provoking phenomenological theories have been put forward. However, these theories have conflicting predictions, and the currently available numerical simulations are not able to resolve the contradictions. MHD turbulence exhibits a variety of regimes unusual in regular hydrodynamic turbulence. Depending on the strength of the guide magnetic field it can be dominated by weakly interacting Alfv\'en waves or strongly interacting wave packets. At small scales such turbulence is locally anisotropic and imbalanced (cross-helical). In a stark contrast with hydrodynamic turbulence, which tends to ``forget'' global constrains and become uniform and isotropic at small scales, MHD turbulence becomes progressively more anisotropic and unbalanced at small scales. Magnetic field plays a fundamental role in turbulent dynamics. Even when such a field is not imposed by external sources, it is self-consistently generated by the magnetic dynamo action. This project aims at a comprehensive study of universal regimes of magnetic plasma turbulence, combining the modern analytic approaches with the state of the art numerical simulations. The proposed study focuses on the three topics: weak MHD turbulence, which is relevant for laboratory devices, the solar wind, solar corona heating, and planetary magnetospheres; strong MHD turbulence, which is relevant for fusion devices, star formation, cosmic rays acceleration, scattering and trapping in galaxies, as well as many aspects of dynamics, distribution and composition of space plasmas, and the process of magnetic dynamo action, which explains the generation and the structure of magnetic fields in turbulent plasmas. The planned work will aim at developing new analytic approaches, conducting new numerical simulations with currently unmatched resolution, and training students in the methods of the modern theory of plasma turbulence. The work will be performed at the University of Wisconsin--Madison.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1972 with total page 1070 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Collisional Drift Waves in Stellarator Plasmas written by Jerome L.V. Lewandowski and published by . This book was released on 2003 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Geometry Dependence of TEM Turbulence in the HSX Stellarator and Comparison to Nonlinear Gyrokinetic Simulation written by Jason Cedric Smoniewski and published by . This book was released on 2021 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: Turbulent transport is responsible for much of the energy and particle losses in present-day fusion plasma experiments, and optimization to reduce turbulence will be a major step towards realizing the benefits of fusion energy. Stellarators, with the flexibility afforded by external coils and three-dimensional geometry, may be able to reduce turbulence through careful shaping of the magnetic field. Such optimization relies on the ability of simulations to accurately predict turbulence in real devices, and validation studies are severely lacking for the stellarator. In this dissertation, the magnetic flexibility of the Helically Symmetric eXperiment (HSX) stellarator is exploited to investigate Trapped Electron Mode (TEM) turbulence in quasi-helically symmetric and degraded-symmetry configurations through experimental measurements and gyrokinetic simulation. This work includes the first comparison of nonlinear simulations in the Quasi-Helically Symmetric (QHS) and Mirror configurations, as well as the first comparison of nonlinear simulations at experimental parameters to experimental measurements. A database of archived HSX plasma discharges has enabled the temperature and density profiles to be matched in QHS and Mirror, showing that thermal transport is larger in the Mirror configuration at the mid-radius. Simulations do not reproduce this difference between geometries, but transport is sensitive to whether turbulence is in a ∇[n]-driven or ∇[T][e]-driven regime. More precise gradient measurements would be required for full validation of this geometry dependence. While linear growth rates are not predictive of overall turbulence, general aspects of experimental transport are captured by nonlinear simulations. In both simulation and experiment, the heat flux and density fluctuation amplitude increase more strongly with the density gradient than the temperature gradient, and the simulated heat flux matches measurements within experimental uncertainties for both configurations. This confirms that ∇[n]-driven TEM turbulence is the dominant driver of anomalous transport in HSX. Zonal flows can be important to TEM turbulence saturation, and are present in all nonlinear simulations of HSX. This work includes the first calculation of the linear collisionless zonal flow damping in quasi-symmetric magnetic geometry. Flux-tube, flux-surface, and full-volume calculations of the zonal flow evolution and residual are compared in the QHS and Mirror configurations, as well as the quasi-axial symmetry of the National Compact Stellarator eXperiment (NCSX). Despite quasi-symmetry, the dynamics of the zonal flow in all three configurations are similar to those in a conventional stellarator. The zonal flow oscillation presents another opportunity for comparison between simulation and experiment, but measurement of the zonal flow is left to future work. This dissertation is only the starting point for a validation study on the HSX stellarator. Significant opportunities exist for updated experimental measurements and a deeper investigation into the nonlinear physics responsible for TEM dynamics.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1967 with total page 1030 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics Briefs written by and published by . This book was released on 1991 with total page 1132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
