On Anomalous Plasma Transport in the Edge of Magnetic Confinement Devices

On Anomalous Plasma Transport in the Edge of Magnetic Confinement Devices
Author: Justin Ray Angus
Publisher:
Total Pages: 98
Release: 2012
Genre:
ISBN: 9781267792181

Magnetic confinement devices use strong magnetic fields to confine fusion grade plasmas for the purpose of producing fusion energy. Fully understanding plasma transport in these devices is crucial for the realization of a fusion reactor. The plasma transport is governed mostly by anomalous (turbulent) processes. Furthermore, the edge region is characterized by strong gradients in plasma profiles leading to coherent convecting structures known as plasma blobs that can dominant the far edge transport. This Thesis work is concerned with a characterization of plasma blob dynamics through a combination of theoretical investigations and 3D simulations of the collisional Braginskii equations using the code BOUT++. Another topic of this Thesis is the modeling of mean profile evolution due to fluctuating anomalous transport. The model is a formulated as a kinetic extension of fluid models and is implemented into the 2D2V gyrokinetic code COGENT.

On the Edge of Magnetic Fusion Devices

On the Edge of Magnetic Fusion Devices
Author: Sergei Krasheninnikov
Publisher: Springer Nature
Total Pages: 269
Release: 2020-09-07
Genre: Science
ISBN: 3030495949

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.

Turbulent Transport In Magnetized Plasmas

Turbulent Transport In Magnetized Plasmas
Author: C Wendell Horton, Jr
Publisher: World Scientific
Total Pages: 518
Release: 2012-08-22
Genre: Science
ISBN: 9814483885

The book explains how magnetized plasmas self-organize in states of electromagnetic turbulence that transports particles and energy out of the core plasma faster than anticipated by the fusion scientists designing magnetic confinement systems in the 20th century. It describes theory, experiments and simulations in a unified and up-to-date presentation of the issues of achieving nuclear fusion power.

Plasma Confinement

Plasma Confinement
Author: R. D. Hazeltine
Publisher: Courier Corporation
Total Pages: 484
Release: 2003-01-01
Genre: Science
ISBN: 9780486432427

Graduate-level text examines the essential physics underlying international research in magnetic confinement fusion with accounts of fundamental concepts behind methods of confining plasma at or near thermonuclear conditions. 1992 edition.

The Plasma Boundary of Magnetic Fusion Devices

The Plasma Boundary of Magnetic Fusion Devices
Author: P.C Stangeby
Publisher: CRC Press
Total Pages: 738
Release: 2000-01-01
Genre: Science
ISBN: 9780750305594

The Plasma Boundary of Magnetic Fusion Devices introduces the physics of the plasma boundary region, including plasma-surface interactions, with an emphasis on those occurring in magnetically confined fusion plasmas. The book covers plasma-surface interaction, Debye sheaths, sputtering, scrape-off layers, plasma impurities, recycling and control, 1D and 2D fluid and kinetic modeling of particle transport, plasma properties at the edge, diverter and limiter physics, and control of the plasma boundary. Divided into three parts, the book begins with Part 1, an introduction to the plasma boundary. The derivations are heuristic and worked problems help crystallize physical intuition, which is emphasized throughout. Part 2 provides an introduction to methods of modeling the plasma edge region and for interpreting computer code results. Part 3 presents a collection of essays on currently active research hot topics. With an extensive bibliography and index, this book is an invaluable first port-of-call for researchers interested in plasma-surface interactions.

Transport and Confinement in Toroidal Devices, 2nd Workshop on Magnetic Confinement Fusion

Transport and Confinement in Toroidal Devices, 2nd Workshop on Magnetic Confinement Fusion
Author: Carlos Alejaldre
Publisher: CRC Press
Total Pages: 178
Release: 1992
Genre: Controlled fusion
ISBN:

This text and software package contains many of the formulae needed for researchers to compute atomic processes, including photoionization, Auger and radiative decay, elastic scattering and ionization. The calculations are set within the Hartree-Fock approximation and its generalization to the random phase approximation with exchange. The results of calculations can be used to solve a wide range of physical problems, from atomic structure to cross sections of collision processes.It explains how to use the ATOM programs, the software for which is written in FORTRAN and may be used on VAX or UNIX-based machines. The programs each consider a different range of variables. The organization of the text and software is designed to help the user calculate what they need to as easily as possible.

Aspects of Anomalous Transport in Plasmas

Aspects of Anomalous Transport in Plasmas
Author: Radu Balescu
Publisher: CRC Press
Total Pages: 319
Release: 2005-04-01
Genre: Science
ISBN: 9780750310307

Anomalous transport is a ubiquitous phenomenon in astrophysical, geophysical and laboratory plasmas; and is a key topic in controlled nuclear fusion research. Despite its fundamental importance and ongoing research interest, a full understanding of anomalous transport in plasmas is still incomplete, due to the complexity of the nonlinear phenomena involved. Aspects in Anomalous Transport in Plasmas is the first book to systematically consider anomalous plasma transport theory and provides a unification of the many theoretical models by emphasizing interrelations between seemingly different methodologies. It is not intended as a catalogue of the vast number of plasma instabilities leading to anomalous transport; instead it chooses a number of these and emphasizes the aspects specifically due to turbulence. After a brief introduction, the microscopic theory of turbulence is discussed, including quasilinear theory and various aspects of renormalization methods, which leads to an understanding of resonance broadening, mode coupling, trajectory correlation and clumps. The second half of the book is devoted to stochiastic tramsport, using methods based on the Langevin equations and on Random Walk theory. This treatment aims at going beyond the traditional limits of weak turbulence, by introducing the recently developed method of decorrelation trajectories, and its application to electrostatic turbulence, magnetic turbulence and zonal flow generation. The final chapter includes very recent work on the nonlocal transport phenomenon.

Fluctuation Induced Cross-field Transport in Hall Thrusters and Tokamaks

Fluctuation Induced Cross-field Transport in Hall Thrusters and Tokamaks
Author: Michael Lane Garrett
Publisher:
Total Pages: 120
Release: 2013
Genre:
ISBN:

One area of fundamental plasma physics which remains poorly understood is the transport of particles across magnetic field lines at rates significantly higher than predicted by theory exclusively based on collisions. This "anomalous" transport is observed in many different classes of plasma experiment. Notably, both magnetic confinement fusion devices and Hall thrusters exhibit anomalous cross-field particle diffusion. This higher than predicted "loss" of particles has significant practical implications for both classes of experiment. In the case of magnetic confinement fusion experiments, such as tokamaks, the Lawson criterion nT[tau]E >/= 1021 [keV. s. M- 3] dictates that the reactant particles in a fusion plasma must be confined for a sufficient time to fuse. Higher than predicted cross-field transport decreases the effectiveness of the magnetic confinement and makes fusion more difficult to achieve. For Hall thrusters, enhanced cross-field electron mobility reduces the efficiency of the thruster. As a result, more propellant and power is required to achieve the same thrust. The goal of this thesis is to review observed and predicted fluctuation induced particle transport in Hall thrusters and tokamaks. To date, significant work has been done within both the tokamak and propulsion communities to attempt to quantify the effect of turbulent fluctuations of plasma parameters on anomalous cross-field transport. However, our understanding of the fundamental physical processes that lead to anomalously high cross-field transport remains incomplete. These two regimes of plasma physics are very different in several important ways. The magnetic field strength and field orientation, the device size, the collisionality of different species, the ion mass, and the presence of neutrals are all areas with significant differences between tokamaks and Hall thrusters. However, there are similarities as well. For example, the edge density and temperature in a tokamak are similar to those found in Hall thrusters, both have magnetized electrons, drift waves occur in both regimes and many of the observed fluctuations are of similar scale. Generally, research on cross-field transport within the tokamak community is isolated from work done within the thruster community. However, analysis of physics within both regimes reveals a rich set of complex fluctuations across a broad frequency spectrum, which contribute to cross-field transport. By studying the relevant phenomena in tandem, we can reveal fundamental processes present in both regimes. Hopefully, this will lead to a global explanation for these elusive physical processes.

Turbulent Transport in Magnetized Plasmas

Turbulent Transport in Magnetized Plasmas
Author: C. Wendell Horton Jr
Publisher: World Scientific Publishing Company
Total Pages: 507
Release: 2017-06-02
Genre: Science
ISBN: 9789813225886

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.