Download or read book Continuum Kinetic Modeling of the Tokamak Plasma Edge written by and published by . This book was released on 2016 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study, the first 4D (axisymmetric) high-order continuum gyrokinetic transport simulations that span the magnetic separatrix of a tokamak are presented. The modeling is performed with the COGENT code, which is distinguished by fourth-order finite-volume discretization combined with mapped multiblock grid technology to handle the strong anisotropy of plasmatransport and the complex X-point divertor geometry with high accuracy. The calculations take into account the effects of fully nonlinear Fokker-Plank collisions, electrostatic potential variations, and anomalous radial transport. Topics discussed include: (a) ion orbit loss and the associated toroidal rotation and (b) edge plasma relaxation in the presence of anomalous radial transport.
Download or read book Continuum Gyrokinetic Edge New Technology written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: COGENT is a simulation code that models the plasma evolution in the edge region of a tokamak fusion reactor, from the open field line scrape-off layer, across the separatrix, and into the core. The model is based on the 4D gyrokinetic closure of the kinetic equations for a plasma coupled to an electrostatic potential field. The background magnetic field is prescribed either analytically or generated from experimental data, and the grid is aligned with magnetic flux surfaces. Multiple collision operator options are provided, from Krook to fully nonlinear Fokker-Planck.
Download or read book Two dimensional Kinetic Modeling of a Tokamak Scrape off Layer with Recycling written by Per O. F. Helander and published by . This book was released on 1993 with total page 17 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling of the Plasma Edge in Fusion Tokamaks written by Marcus Steven Day and published by . This book was released on 1992 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neoclassical Simulation of Tokamak Plasmas Using Continuum Gyrokinetc Code TEMPEST written by and published by . This book was released on 2007 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: We present gyrokinetic neoclassical simulations of tokamak plasmas with self-consistent electric field for the first time using a fully nonlinear (full-f) continuum code TEMPEST in a circular geometry. A set of gyrokinetic equations are discretized on a five dimensional computational grid in phase space. The present implementation is a Method of Lines approach where the phase-space derivatives are discretized with finite differences and implicit backwards differencing formulas are used to advance the system in time. The fully nonlinear Boltzmann model is used for electrons. The neoclassical electric field is obtained by solving gyrokinetic Poisson equation with self-consistent poloidal variation. With our 4D ([psi], [theta], [epsilon], [mu]) version of the TEMPEST code we compute radial particle and heat flux, the Geodesic-Acoustic Mode (GAM), and the development of neoclassical electric field, which we compare with neoclassical theory with a Lorentz collision model. The present work provides a numerical scheme and a new capability for self-consistently studying important aspects of neoclassical transport and rotations in toroidal magnetic fusion devices.
Download or read book Tokamak Plasma written by B. B. Kadomtsev and published by CRC Press. This book was released on 1992 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: The importance of tokamaks and their role in fusion reactors has been known for some time, but it is only now that plasma physicists have reached a clear understanding of the major principles governing the behaviour of confined high-temperature plasma. This book gives a timely and comprehensive survey of these concepts as well as a simple presentation of the basic physics involved. The topics discussed include: the theory of plasma equilibrium and its main instabilities, semi-empirical approaches for investigating heat transport, major plasma instabilities restricting the region of a tokamak's operating modes, a variety of plasma confinement regimes and other phenomena such as MARFE, magnetic bubbles and fishbones. The author proposes a new mechanism for anomalous heat transport connected with the idea of microscale 'island' structure. The information is presented in a clear and systematic way which will make this book interesting and useful to a broad spectrum of scientists and engineers involved in fusion reactor research. '...an excellent book - authoritative, broad and bristling with insight' Professor R D Hazeltine, The University of Texas at Austin.
Download or read book Theory of Tokamak Plasmas written by R.B. White and published by Elsevier. This book was released on 2017-01-31 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a graduate textbook on tokamak physics, designed to provide a basic introduction to plasma equilibrium, particle orbits, transport, and those ideal and resistive magnetohydrodynamic instabilities which dominate the behavior of a tokamak discharge, and to develop the mathematical methods necessary for their theoretical analysis.
Download or read book Plasma Edge Model for Tokamaks written by Michael Raymond Gordinier and published by . This book was released on 1980 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modeling the Turbulent Momentum Transport in Tokamak Plasmas written by Pierre Cottier and published by LAP Lambert Academic Publishing. This book was released on 2014-04-01 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The magnetic confinement in tokamaks is for now the most advanced way towards energy production by nuclear fusion. Both theoretical and experimental studies showed that rotation generation can increase its performance by reducing the turbulent transport in tokamak plasmas. The rotation influence on the heat and particle fluxes is studied along with the angular momentum transport with the quasi-linear gyro-kinetic eigenvalue code QuaLiKiz. For this purpose, the QuaLiKiz code is modified in order to take the plasma rotation into account and compute the angular momentum flux. It is shown that QuaLiKiz framework is able to correctly predict the angular momentum flux including the ExB shear induced residual stress as well as the influence of rotation on the heat and particle fluxes. The different contributions to the turbulent momentum flux are studied and successfully compared against both non-linear gyro-kinetic simulations and experimental data.
Download or read book Magnetic Fluctuations in Gyrokinetic Simulations of Tokamak Scrape Off Layer Turbulence written by Noah Roth Mandell and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding turbulent transport physics in the tokamak edge and scrape-off layer (SOL) is critical to developing a successful fusion reactor. The dynamics in these regions plays a key role in achieving high fusion performance by determining the edge pedestal that suppresses turbulence in the high-confinement mode (H-mode). Additionally, the survivability of a reactor is set by the heat load to the vessel walls, making it important to understand turbulent spreading of heat as it flows along open magnetic field lines in the SOL. Large-amplitude fluctuations, magnetic X-point geometry, and plasma interactions with material walls make simulating turbulence in the edge/SOL more challenging than in the core region, necessitating specialized gyrokinetic codes. Further, the inclusion of electromagnetic effects in gyrokinetic simulations that can handle the unique challenges of the boundary plasma is critical to the understanding of phenomena such as the pedestal and edge-localized modes, for which electromagnetic dynamics are expected to be important.In this thesis, we develop the first capability to simulate electromagnetic gyrokinetic turbulence on open magnetic field lines. This is an important step towards comprehensive electromagnetic gyrokinetic simulations of the coupled edge/SOL system. By using a continuum full-f approach via an energy-conserving discontinuous Galerkin (DG) discretization scheme that avoids the Ampere cancellation problem, we show that electromagnetic fluctuations can be handled in a robust, stable, and efficient manner in the gyrokinetic module of the Gkeyll code. We then present results which roughly model the scrape-off layer of the National Spherical Torus Experiment (NSTX), and show that electromagnetic effects can affect blob dynamics and transport. We also formulate the gyrokinetic system in field-aligned coordinates for modeling realistic edge and scrape-off layer geometries in experiments. A novel DG algorithm for maintaining positivity of the distribution function while preserving conservation laws is also presented.
Download or read book Tokamaks written by John Wesson and published by Oxford University Press. This book was released on 2011-10-13 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt: The tokamak is the principal tool in controlled fusion research. This book acts as an introduction to the subject and a basic reference for theory, definitions, equations, and experimental results. The fourth edition has been completely revised, describing their development of tokamaks to the point of producing significant fusion power.
Download or read book Kinetic and Transport Theory Near the Tokamak Edge written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Conventional transport orderings employed in the core of a tokamak plasma allow large divergence-free flows in flux surfaces, but only weak radial flows. However, alternate orderings are required in the edge region where radial diffusion must balance the rapid loss due to free-streaming to divertor plates or limiters. Kinetic equations commonly used to study the plasma core do not allow such a balance and are, therefore, inapplicable in the plasma edge. Similarly, core transport formulae cannot be extended to the edge region without major, qualitative alteration. Here the authors address the necessary changes. By deriving and solving a novel kinetic equation, they construct distinctive collisional transport laws for the plasma edge. They find that their edge ordering naturally retains the radial diffusion and parallel flow of particles, momentum and heat to lowest order in the conservation equations. To higher order they find a surprising form for parallel transport in the scrape-off layer, in which the parallel flow of particles and heat are driven by a combination of the conventional gradients, viscosity, and new terms involving radial derivatives. The new terms are not relatively small, and could affect understanding of limiter and divertor operation.
Download or read book Towards a More Complete Description of Tokamak Edge Plasmas written by Menglong Zhao and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book TEMPEST Simulations of the Plasma Transport in a Single Null Tokamak Geometry written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We present edge kinetic ion transport simulations of tokamak plasmas in magnetic divertor geometry using the fully nonlinear (full-f) continuum code TEMPEST. Besides neoclassical transport, a term for divergence of anomalous kinetic radial flux is added to mock up the effect of turbulent transport. In order to study the relative roles of neoclassical and anomalous transport, TEMPEST simulations were carried out for plasma transport and flow dynamics in a single-null tokamak geometry, including the pedestal region that extends across the separatrix into the scrape-off layer and private flux region. In a series of TEMPEST simulations were conducted to investigate the transition of midplane pedestal heat flux and flow from the neoclassical to the turbulent limit and the transition of divertor heat flux and flow from the kinetic to the fluid regime via an anomalous transport scan and a density scan. The TEMPEST simulation results demonstrate that turbulent transport (as modelled by large diffusion) plays a similar role to collisional decorrelation of particle orbits and that the large turbulent transport (large diffusion) leads to an apparent Maxwellianization of the particle distribution. Moreover, we show the transition of parallel heat flux and flow at the entrance to the divertor plates from the fluid to the kinetic regime. For an absorbing divertor plate boundary condition, a non-half-Maxwellian is found due to the balance between upstream radial anomalous transport and energetic ion endloss.
Download or read book On the Edge of Magnetic Fusion Devices written by Sergei Krasheninnikov and published by Springer Nature. This book was released on 2020-09-07 with total page 269 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews the current state of understanding concerning edge plasma, which bridges hot fusion plasma, with a temperature of roughly one million degrees Kelvin with plasma-facing materials, which have melting points of only a few thousand degrees Kelvin. In a fact, edge plasma is one of the keys to solution for harnessing fusion energy in magnetic fusion devices. The physics governing the processes at work in the edge plasma involves classical and anomalous transport of multispecies plasma, neutral gas dynamics, atomic physics effects, radiation transport, plasma-material interactions, and even the transport of plasma species within the plasma-facing materials. The book starts with simple physical models, then moves on to rigorous theoretical considerations and state-of-the-art simulation tools that are capable of capturing the most important features of the edge plasma phenomena. The authors compare the conclusions arising from the theoretical and computational analysis with the available experimental data. They also discuss the remaining gaps in their models and make projections for phenomena related to edge plasma in magnetic fusion reactors.
Download or read book Advanced Tokamak Stability Theory written by Linjin Zheng and published by Morgan & Claypool Publishers. This book was released on 2014-04-01 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the advanced stability theories for magnetically confined fusion plasmas, especially in tokamaks. As the fusion plasma sciences advance, the gap between the textbooks and cutting-edge researches gradually develops. This book fills in
Download or read book Simulation of Neoclassical Transport with the Continuum Gyrokinetic Code COGENT written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
