Download or read book Transport in a Stochastic Magnetic Field written by Jean-Marcel Rax and published by . This book was released on 1992 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Collisionless Transport in a Stochastic Magnetic Field written by R. B. White and published by . This book was released on 1992 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nonlocal Heat Transport in a Stochastic Magnetic Field written by Jean-Marcel Rax and published by . This book was released on 1991 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transport in a Stochastic Magnetic Field written by and published by . This book was released on 1992 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Collisional heat transport in a stochastic magnetic field configuration is investigated. Well above stochastic threshold, a numerical solution of a Chirikov-Taylor model shows a short-time nonlocal regime, but at large time the Rechester-Rosenbluth effective diffusion is confirmed. Near stochastic threshold, subdiffusive behavior is observed for short mean free paths. The nature of this subdiffusive behavior is understood in terms of the spectrum of islands in the stochastic sea.

Download or read book Nonlocal Heat Transport in a Stochastic Magnetic Field written by and published by . This book was released on 1991 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: Heat transport in a stochastic magnetic field configuration is shown to be nonlocal. Collisional transport processes, in such a disordered media, cannot always be reduced to a standard diffusion process, and the concept of a diffusion coefficient is meaningless for a wide range of typical tokamak parameters. In the nonlocal regime the relaxation of a gradient is described by an integral equation, involving a nonlocal propagator. This propagator is calculated, and the relation to previous results is elucidated. 15 refs.

Download or read book Plasma Transport in Stochastic Magnetic Fields I written by John A. Krommes and published by . This book was released on 1978 with total page 97 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plasma Transport in Stochastic Magnetic Fields I General Considerations and Test Particle Transport written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A systematic theory is developed for the computation of electron transport in stochastic magnetic fields. Small scale magnetic perturbations arising, for example, from finite-.beta. micro-instabilities are assumed to destroy the flux surfaces of a standard tokamak equilibrium. Because the magnetic lines then wander in a volume, electron radial flux is enhanced due to the rapid particle transport along as well as across the lines. By treating the magnetic lines as random variables, it is possible to develop a kinetic equation for the electron distribution function. This is solved approximately to yield the diffusion coefficient.

Download or read book Plasma Transport in Stochastic Magnetic Fields III Kinetics of Test particle Diffusion written by and published by . This book was released on 1982 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A discussion is given of test particle transport in the presence of specified stochastic magnetic fields, with particular emphasis on the collisional limit. Certain paradoxes and inconsistencies in the literature regarding the form of the scaling laws are resolved by carefully distinguishing a number of physically distinct correlation lengths, and thus by identifying several collisional subregimes. The common procedure of averaging the conventional fluid equations over the statistics of a random field is shown to fail in some important cases because of breakdown of the Chapman-Enskog ordering in the presence of a stochastic field component with short autocorrelation length. A modified perturbation theory is introduced which leads to a Kubo-like formula valid in all collisionality regimes. The direct-interaction approximation is shown to fail in the interesting limit in which the orbit exponentiation length L/sub K/ appears explicitly. A higher order renormalized kinetic theory in which L/sub K/ appears naturally is discussed and used to rederive more systematically the results of the heuristic scaling arguments.

Download or read book Plasma Transport in Stochastic Magnetic Fields II written by John A. Krommes and published by . This book was released on 1978 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plasma Transport in Stochastic Magnetic Fields III written by John A. Krommes and published by . This book was released on 1982 with total page 65 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plasma Transport in Stochastic Magnetic Field Caused by Vacuum Resonant Magnetic Perturbations at Diverted Tokamak Edge written by and published by . This book was released on 2010 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Plasma Transport in Stochastic Magnetic Fields II Principles and Problems of Test Electron Transport written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A model stochastic differential equation is considered which describes guiding center electron motion in a statistically specified spectrum of turbulent magnetic fluctuations. The fluctuation intensity is assumed to satisfy the Chirikov criterion (resonance overlap) for onset of stochasticity. In this limit typical lines diffuse and are adequately described by a quasilinear diffusion coefficient D/sub m/. However, quasilinear theory does not describe an important mechanism for loss of particle correlations: particles collisionally diffuse from one line to an adjacent one which diverges rapidly from the first, carrying the particles away. The scale length L/sub K/ for line divergence is related to the inverse of the Kolmogorov-Sinai entropy. An attempt is made to determine L/sub K/ from a simplified Eulerian vertex renormalization. The exponentiation length which emerges is L/sub K/ approximately L/sub s/(anti k2/sub theta/D''/sub m/L/sub s/)−13, where L/sub s/ is the shear length, k bar/sub theta/ is a typical azimuthal wavenumber, and D''/sub m/ is of order D/sub m/. In a particular limit of weak shear, the particle diffusion coefficient can then be estimated as D approximately DELTA r2?sub c/, where .delta.r2 approximately D/sub m/z(tau/sub c/), z? is the distance traveled along the lines in time tau, and for static fluctuations tau/sub c/ approximately tau(L/sub delta/), where L/sub delta/ is L/sub K/ multiplied by a logarithmic factor involving the perpendicular collisional diffusion coefficient.

Download or read book Transport Phenomena in Stochastic Magnetic Mirrors written by Leonid M. Malyshkin and published by . This book was released on 2000 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Magnetic Stochasticity in Magnetically Confined Fusion Plasmas written by Sadrilla Abdullaev and published by Springer Science & Business Media. This book was released on 2013-11-19 with total page 422 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 Momentum and Heat Transport in MHD Turbulence in Presence of Stochastic Magnetic Fields written by Changchun Chen and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Tangled magnetic fields, often coexisting with an ordered mean field, have a major impact on turbulence and momentum transport in many plasmas, including those found in the solar tachocline and magnetic confinement devices. In this dissertation, we present research on the turbulent transport in presence of a stochastic magnetic field, and the discuss implications on the formation of astronomical objects and on the turbulence in edge plasma in fusion devices. The research is divided into three projects. First, we present a novel mean field theory of potential vorticity mixing in [beta]-plane magnetohydrodynamic (MHD). Our results show that mean square stochastic fields strongly reduce Reynolds stress coherence. This decoherence of potential vorticity flux due to stochastic field scattering leads to suppression of momentum transport and zonal flow formation. We discuss a model of stochastic fields as a resisto-elastic network. In second project, we shows the breaking of the shear-eddy tilting feedback loop by stochastic fields is the key underlying physics mechanism. A simple calculation suggests that the breaking of the shear-eddy tilting feedback loop by stochastic fields is the key underlying physics mechanism. A dimensionless parameter that quantifies the increment in power threshold is identified and used to assess the impact of stochastic field on the L-H transition in fusion devices. Finally, we study the turbulent transport of parallel momentum and ion heat by the interaction of stochastic magnetic fields and turbulence in third project. Attention is focused on determining the kinetic stress and the compressive energy flux. A critical parameter is identified as the ratio of the turbulent scattering rate to the rate of parallel acoustic dispersion. For the parameter large, the kinetic stress takes the form of a viscous stress. For the parameter small, the quasilinear residual stress is recovered. In practice, the viscous stress is the relevant form, and the quasilinear limit is not observable. This is the principal prediction of this project.

Download or read book Studies of Transport in Random Magnetic Field written by Karén Chaltikian and published by . This book was released on 1997 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transport Phenomena in Stochastic Magnetic Mirrors written by Leonid M. Malyshkin and published by . This book was released on 2000 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: