Download or read book Nondimensional Transport Experiments on DIII D and Projections to an Ignition Tokamak written by and published by . This book was released on 1996 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The concept of nondimensional scaling of transport makes it possible to determine the required size for an ignition device based upon data from a single machine and illuminates the underlying physics of anomalous transport. The scaling of cross-field heat transport with the relative gyroradius [rho]*, the gyroradius normalized to the plasma minor radius, is of particular interest since [rho]* is the only nondimensional parameter which will vary significantly between present day machines and an ignition device. These nondimensional scaling experiments are based upon theoretical considerations which indicate that the thermal heat diffusivity can be written in the form [chi] = [chi]{sub B}[rho]*{sup x{sub [rho]}} F([beta], v*, q, R/a, [kappa], T{sub e}/T{sub i} ...), where [chi]{sub B} = cT/eB. As explained elsewhere, x{sub {rho}} = 1 is called gyro-Bohm scaling, x{sub {rho}} is Bohm scaling, x{sub {rho}} = -1/2 is Goldston scaling, and x{sub {rho}} = -1 is stochastic scaling. The DIII-D results reported in this paper cover three important aspects of nondimensional scaling experiments: the testing of the underlying assumption of the nondimensional scaling approach, the determination of the {rho}* scaling of heat transport for various plasma regimes, and the extrapolation of the energy confinement time to future ignition devices.
Download or read book Nondimensional Transport Scaling in DIII D written by and published by . This book was released on 1995 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comprehensive Energy Transport Scalings Derived from DIII D Similarity Experiments written by and published by . This book was released on 1998 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Primer on Complex Systems written by Raúl Sánchez and published by Springer. This book was released on 2018-03-08 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this book is to illustrate the fundamental concepts of complexity and complex behavior and the best methods to characterize this behavior by means of their applications to some current research topics from within the fields of fusion, earth and solar plasmas. In this sense, it is a departure from the many books already available that discuss general features of complexity. The book is divided in two parts. In the first part the most important properties and features of complex systems are introduced, discussed and illustrated. The second part discusses several instances of possible complex phenomena in magnetized plasmas and some of the analysis tools that were introduced in the first part are used to characterize the dynamics in these systems. A list of problems is proposed at the end of each chapter. This book is intended for graduate and post-graduate students with a solid college background in mathematics and classical physics, who intend to work in the field of plasma physics and, in particular, plasma turbulence. It will also be of interest to senior scientists who have so far approached these systems and problems from a different perspective and want a new fresh angle.
Download or read book BETA SCALING OF TRANSPORT ON THE DIII D TOKAMAK IS TRANSPORTELECTROSTATIC OR ELECTROMAGNETIC written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Determining the scaling of transport with ([beta]), the ratio of the plasma kinetic pressure to the magnetic pressure, helps to differentiate between various proposed theories of turbulent transport since mechanisms that are primarily electrostatic show little change in transport with increasing [beta], while primarily electromagnetic mechanisms generally have a strong unfavorable [beta] scaling. Experiments on the DIII-D tokamak have measured the [beta] scaling of heat transport with all of the other dimensionless parameters held constant in high confinement mode (H-mode) plasmas with edge localized modes (ELMs). A four point scan varied [beta] from 30% to 85% of the ideal ballooning stability limit (normalized beta from 1.0 to 2.8) and found no change in the normalized confinement time, i.e., B[tau][sub th] [infinity] [beta][sup -0.01] [+-] 0.09. The measured thermal diffusivities, normalized to the Bohm diffusion coefficient, also did not vary during the [beta] can to within the experimental uncertainties, whereas the normalized helium particle transport decreased with increasing [beta]. The H-mode pedestal [beta] varied in concert with the core [beta] and showed no signs of saturation. This weak, possibly non-existent, [beta] scaling of transport favors primarily electrostatic mechanisms such as E x B transport, and is in marked disagreement with the strong unfavorable [beta] dependence contained in empirical scaling relations derived from multi-machine H-mode confinement databases.
Download or read book Understanding Transport Through Dimensionless Parameter Scaling Experiments written by and published by . This book was released on 1997 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The related methods of dimensional analysis, similarity, and scale invariance provide a powerful technique for analyzing physical systems. For example, the complex plasma dynamics governed by the Vlasov-Maxwell system of equations can be characterized by sets of dimensionless quantities through the application of these techniques. Significant progress has been made recently towards predicting and understanding radial heat transport using dimensionless parameter scaling techniques. Previous experiments on the DIII-D tokamak have measured the variation of heat transport with the relative gyroradius ([rho]*); in this paper, the scaling of heat transport with plasma beta ([beta]) and normalized collisionality ([nu]) for L-mode and H-mode plasmas on the DIII-D tokamak is reported. Following the scale invariance approach to confinement scaling, the thermal diffusivity ([chi]) is assumed to depend only on local dimensionless quantities. Understanding the beta and collisionality scaling of transport helps to differentiate between various proposed mechanisms of turbulent transport and allows the origin of power degradation and density scaling of confinement to be determined.
Download or read book Self Organization of Hot Plasmas written by Yu.N. Dnestrovskij and published by Springer. This book was released on 2014-07-08 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this monograph the author presents the Canonical Profile Transport Model or CPTM as a rather general mathematical framework to simulate plasma discharges. The description of hot plasmas in a magnetic fusion device is a very challenging task and many plasma properties still lack a physical explanation. One important property is plasma self-organization. It is very well known from experiments that the radial profile of the plasma pressure and temperature remains rather unaffected by changes of the deposited power or plasma density. The attractiveness of the CPTM is that it includes the effect of self-organization in the mathematical model without having to recur to particular physical mechanisms. The CPTM model contains one dimensional transport equations for ion and electron temperatures, plasma density and toroidal rotation velocity. These equations are well established and in fact are essentially a reformulation the laws of energy, particle and momentum conservation. But the expressions for the energy and particle fluxes, including certain critical gradients, are new. These critical gradients can be determined using the concept of canonical profiles for the first time formulated in great detail in the book. This concept represents a totally new approach to the description of transport in plasmas. Mathematically, the canonical profiles are formulated as a variational problem. To describe the temporal evolution of the plasma profiles, the Euler equation defining the canonical profiles is solved together with the transport equations at each time step. The author shows that in this way it is possible to describe very different operational scenarios in tokamaks (L-Mode, H-Mode, Advanced Modes, Radiating Improved Modes etc...), using one unique principle. The author illustrates the application of this principle to the simulation of plasmas on leading tokamak devices in the world (JET, MAST, T-10, DIII-D, ASDEX-U, JT-60U). In all cases the small differences between the calculated profiles for the ion and electron temperatures and the experimental is rather confirm the validity of the CPTM. In addition, the model also describes the temperature and density pedestals in the H-mode and non steady-state regimes with current and density ramp up. The proposed model therefore provides a very useful mathematical tool for the analysis of experimental results and for the prediction of plasma parameters in future experiments.
Download or read book Experimental Constraints on Transport from Dimensionless Parameter Scaling Studies written by and published by . This book was released on 1998 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Determination of the Dimensionless Scaling Parameter of Energy Transport in Tokamaks written by and published by . This book was released on 1995 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: Controlled fusion experiments have focused on the variation of the plasma characteristics as the engineering or control parameters are systematically changed. This has led to the development of extrapolation formulae for prediction of future device performance using these same variables as a basis. Recently, it was noticed that present-day tokamaks can operate with all of the dimensionless variables which appear in the Vlasov-Maxwell system of equations at values projected for a fusion powerplant with the exception of the parameter [rho]{sub *}, the gyroradius normalized to the machine size. The scaling with this parameter is related to the benefit of increasing the size of the machine either directly or effectively by increasing the magnetic field. It is exactly this scaling which is subject to systematic error in the inter-machine databases and the cost driver for any future machine. If this scaling can be fixed by a series of single machine experiments, much as the current and power scalings have been, the confidence in the prediction of future device performance would be greatly enhanced. While carrying out experiments of this type, it was also found that the [rho]{sub *} scaling can illuminate the underlying physics of energy transport. Conclusions drawn from experiments on the DIII-D tokamak in these two areas are the subject of this paper.
Download or read book 16th IEEE NPSS Symposium Fusion Engineering written by and published by . This book was released on 1995 with total page 900 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 23rd European Physical Society Conference on Controlled Fusion and Plasma Physics written by and published by . This book was released on 1996 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Safety Factor Scaling of Energy Transport in L Mode Plasmas on the DIII D Tokamak written by and published by . This book was released on 2003 with total page 29 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stability and Transport in Magnetic Confinement Systems written by Jan Weiland and published by Springer Science & Business Media. This book was released on 2012-06-27 with total page 235 pages. Available in PDF, EPUB and Kindle. Book excerpt: Stability and Transport in Magnetic Confinement Systems provides an advanced introduction to the fields of stability and transport in tokamaks. It serves as a reference for researchers with its highly-detailed theoretical background, and contains new results in the areas of analytical nonlinear theory of transport using kinetic theory and fluid closure. The use of fluid descriptions for advanced stability and transport problems provide the reader with a better understanding of this topic. In addition, the areas of nonlinear kinetic theory and fluid closure gives the researcher the basic knowledge of a highly relevant area to the present development of transport physics.
Download or read book Magnetic Fusion Energy written by George Neilson and published by Woodhead Publishing. This book was released on 2016-06-02 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic Fusion Energy: From Experiments to Power Plants is a timely exploration of the field, giving readers an understanding of the experiments that brought us to the threshold of the ITER era, as well as the physics and technology research needed to take us beyond ITER to commercial fusion power plants. With the start of ITER construction, the world’s magnetic fusion energy (MFE) enterprise has begun a new era. The ITER scientific and technical (S&T) basis is the result of research on many fusion plasma physics experiments over a period of decades. Besides ITER, the scope of fusion research must be broadened to create the S&T basis for practical fusion power plants, systems that will continuously convert the energy released from a burning plasma to usable electricity, operating for years with only occasional interruptions for scheduled maintenance. Provides researchers in academia and industry with an authoritative overview of the significant fusion energy experiments Considers the pathway towards future development of magnetic fusion energy power plants Contains experts contributions from editors and others who are well known in the field
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 Driven Rotation Self Generated Flow and Momentum Transport in Tokamak Plasmas written by John Rice and published by Springer Nature. This book was released on 2022-01-13 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive look at the state of the art of externally driven and self-generated rotation as well as momentum transport in tokamak plasmas. In addition to recent developments, the book includes a review of rotation measurement techniques, measurements of directly and indirectly driven rotation, momentum sinks, self-generated flow, and momentum transport. These results are presented alongside summaries of prevailing theory and are compared to predictions, bringing together both experimental and theoretical perspectives for a broad look at the field. Both researchers and graduate students in the field of plasma physics will find this book to be a useful reference. Although there is an emphasis on tokamaks, a number of the concepts are also relevant to other configurations.
