Predictive Models For The Edge Of Tokamak H Mode Plasmas

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Predictive Models for the Edge of Tokamak H-mode Plasmas

Author : Thawatchai Onjun
Publisher :
ISBN 13 :
Total Pages : 330 pages
Book Rating : 4.:/5 (573 download)

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Book Synopsis Predictive Models for the Edge of Tokamak H-mode Plasmas by : Thawatchai Onjun

Download or read book Predictive Models for the Edge of Tokamak H-mode Plasmas written by Thawatchai Onjun and published by . This book was released on 2004 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: High confinement (H-mode) discharges in tokamak experiments are characterized by a narrow region of steep pressure gradient called the "pedestal" that forms at the edge of the plasma, and often by an instability called an "Edge Localized Mode (ELM)" that periodically removes energy and particles from the edge of the plasma. The parameters at the top of the pedestal and the characteristics of ELMs have a strong influence on the performance of H-mode discharges. In this study, models for the pedestal are developed initially without including the effects of ELMs. The predictions from these pedestal models yield reasonable agreement with experimental data. These pedestal models are then used to provide boundary conditions in an integrated modeling code in order to simulate plasma profiles, such as temperature and density profiles, in existing H-mode experiments. The simulated profiles obtained using predictive boundary conditions and those obtained using experimental boundary conditions have similar agreement with experimental profiles. A more advanced pedestal model with a dynamic model for ELM crashes is developed using a concept of turbulence suppression at the edge of plasma. These pedestal and ELM models are coupled with a core transport model in an integrated modeling code. An advantage of this approach is that it allows for the evolution of plasma pressure and current profiles in the pedestal region, which can lead to an instability that triggers ELM crashes that limit the growth of the pedestal. Pressure-driven ballooning and current-driven peeling instabilities are considered as the possible instabilities that trigger ELM crashes. The combined core and pedestal models, with the effect of ELMs included, are used to study the dependence of triangularity and heating power on the pedestal. An MHD stability analysis is also performed to confirm the validity of these simulations. It is found that plasma edge stability improves as triangularity increases, as a result of access to the second stability region of ballooning modes. Finally, simulations yield a pedestal height with a dependence on heating power similar to that observed experimentally when the ELM crash model is extended to include ELMS triggered by current-driven peeling instabilities.

Edge Electric Field Profiles of H-mode Plasmas in JFT-2M Tokamak

Author : K. Ida
Publisher :
ISBN 13 :
Total Pages : 8 pages
Book Rating : 4.:/5 (911 download)

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Book Synopsis Edge Electric Field Profiles of H-mode Plasmas in JFT-2M Tokamak by : K. Ida

Download or read book Edge Electric Field Profiles of H-mode Plasmas in JFT-2M Tokamak written by K. Ida and published by . This book was released on 1990 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Dissertation Abstracts International

Author :
Publisher :
ISBN 13 :
Total Pages : 886 pages
Book Rating : 4.F/5 ( download)

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Book Synopsis Dissertation Abstracts International by :

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2006 with total page 886 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Edge Poloidal Rotation Profiles of H-mode Plasmas in the JFT-2M Tokamak

Author : K. Ida
Publisher :
ISBN 13 :
Total Pages : 24 pages
Book Rating : 4.:/5 (355 download)

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Book Synopsis Edge Poloidal Rotation Profiles of H-mode Plasmas in the JFT-2M Tokamak by : K. Ida

Download or read book Edge Poloidal Rotation Profiles of H-mode Plasmas in the JFT-2M Tokamak written by K. Ida and published by . This book was released on 1991 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Energy Research Abstracts

Author :
Publisher :
ISBN 13 :
Total Pages : 438 pages
Book Rating : 4.0/5 ( download)

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Book Synopsis Energy Research Abstracts by :

Download or read book Energy Research Abstracts written by and published by . This book was released on 1994-05 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Magnetohydrodynamic Stability of Tokamaks

Author : Hartmut Zohm
Publisher : John Wiley & Sons
ISBN 13 : 3527412328
Total Pages : 254 pages
Book Rating : 4.5/5 (274 download)

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Book Synopsis Magnetohydrodynamic Stability of Tokamaks by : Hartmut Zohm

Download or read book Magnetohydrodynamic Stability of Tokamaks written by Hartmut Zohm and published by John Wiley & Sons. This book was released on 2015-02-09 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book bridges the gap between general plasma physics lectures and the real world problems in MHD stability. In order to support the understanding of concepts and their implication, it refers to real world problems such as toroidal mode coupling or nonlinear evolution in a conceptual and phenomenological approach. Detailed mathematical treatment will involve classical linear stability analysis and an outline of more recent concepts such as the ballooning formalism. The book is based on lectures that the author has given to Master and PhD students in Fusion Plasma Physics. Due its strong link to experimental results in MHD instabilities, the book is also of use to senior researchers in the field, i.e. experimental physicists and engineers in fusion reactor science. The volume is organized in three parts. It starts with an introduction to the MHD equations, a section on toroidal equilibrium (tokamak and stellarator), and on linear stability analysis. Starting from there, the ideal MHD stability of the tokamak configuration will be treated in the second part which is subdivided into current driven and pressure driven MHD. This includes many examples with reference to experimental results for important MHD instabilities such as kinks and their transformation to RWMs, infernal modes, peeling modes, ballooning modes and their relation to ELMs. Finally the coverage is completed by a chapter on resistive stability explaining reconnection and island formation. Again, examples from recent tokamak MHD such as sawteeth, CTMs, NTMs and their relation to disruptions are extensively discussed.

Predictive Integrated Modeling of Low Aspect Ratio Tokamaks and Large Scale Instabilities in Tokamaks

Author : Canh Ngoc Nguyen
Publisher :
ISBN 13 :
Total Pages : 372 pages
Book Rating : 4.:/5 (573 download)

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Book Synopsis Predictive Integrated Modeling of Low Aspect Ratio Tokamaks and Large Scale Instabilities in Tokamaks by : Canh Ngoc Nguyen

Download or read book Predictive Integrated Modeling of Low Aspect Ratio Tokamaks and Large Scale Instabilities in Tokamaks written by Canh Ngoc Nguyen and published by . This book was released on 2004 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: Models for large scale instabilities in tokamaks are developed, and they are tested together with models for transport and other physical processes by comparing the results of BALDUR integrated predictive modeling simulations with experimental data from tokamaks. Simulations are carried out for the low aspect ratio tokamaks, Mega Ampere Spherical Tokamak and the National Spherical Torus Experiment, to test the applicability of models that were developed for conventional tokamaks. The results indicate that neoclassical transport dominates over anomalous transport in the inner third of the plasma. Sawtooth oscillations, which are the result of an instability that periodically redistributes the central part of the plasma profiles, play a significant role by radially spreading the neutral beam injection heating profiles across the broad sawtooth mixing region. Two models for sawtooth oscillations, the Porcelli and the Kadomtsev models, are combined and tested against experimental data from the Joint European Torus and the Tokamak Fusion Test Reactor. Most of the sawtooth crashes are triggered by the m = 1 resistive internal kink mode in the semi-collisional regime. The median sawtooth period increases with increasing magnetic reconnection fraction. The best overall agreement with experimental data is obtained with a magnetic reconnection fraction of approximately 55%. Finally, plasma pressure effects are included in a quasi-linear model for saturated tearing modes, which are instabilities that produce magnetic islands. The model is used in a stand-alone code, and in the BALDUR code, to calculate the widths of saturated magnetic islands in tokamak plasmas with arbitrary cross-section and plasma pressure. The widths of tearing mode islands increase with decreasing aspect ratio and with increasing elongation. Also, the island widths increase when the gradient of the current density increases at the edge of the islands or when the current density inside the islands is suppressed. The widths oscillate in time in response to periodic sawtooth crashes. Local enhancements in the transport produced by magnetic islands have a noticeable effect on global plasma confinement in simulations of low aspect ratio, high beta tokamaks, where saturated tearing mode islands can occur with widths greater than 15% of the plasma minor radius.

Final Report of the Committee on a Strategic Plan for U.S. Burning Plasma Research

Author : National Academies of Sciences, Engineering, and Medicine
Publisher : National Academies Press
ISBN 13 : 0309487463
Total Pages : 341 pages
Book Rating : 4.3/5 (94 download)

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Book Synopsis Final Report of the Committee on a Strategic Plan for U.S. Burning Plasma Research by : National Academies of Sciences, Engineering, and Medicine

Download or read book Final Report of the Committee on a Strategic Plan for U.S. Burning Plasma Research written by National Academies of Sciences, Engineering, and Medicine and published by National Academies Press. This book was released on 2019-05-31 with total page 341 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fusion offers the prospect of virtually unlimited energy. The United States and many nations around the world have made enormous progress toward achieving fusion energy. With ITER scheduled to go online within a decade and demonstrate controlled fusion ten years later, now is the right time for the United States to develop plans to benefit from its investment in burning plasma research and take steps to develop fusion electricity for the nation's future energy needs. At the request of the Department of Energy, the National Academies of Sciences, Engineering, and Medicine organized a committee to develop a strategic plan for U.S. fusion research. The final report's two main recommendations are: (1) The United States should remain an ITER partner as the most cost-effective way to gain experience with a burning plasma at the scale of a power plant. (2) The United States should start a national program of accompanying research and technology leading to the construction of a compact pilot plant that produces electricity from fusion at the lowest possible capital cost.

Electron Heat Transport in Tokamak H-mode Pedestals

Author : Myriam Hamed
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (122 download)

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Book Synopsis Electron Heat Transport in Tokamak H-mode Pedestals by : Myriam Hamed

Download or read book Electron Heat Transport in Tokamak H-mode Pedestals written by Myriam Hamed and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: In H-mode plasmas, the modeling of the pedestal dynamics is an important issue to predict temperature and density profiles in the tokamak edge and therefore in the core. The EPED model, based on the stability of large scales MagnetoHydroDynamic (MHD) modes, is most commonly used to characterize the pedestal region. The EPED model has been successful until now. However, EPED model does not take into account small scales instabilities linked the the sharp pressure gradient and the pedestal characteristics prediction in terms of width and height is still open. Moreover, some recent analysis of JET plasmas suggest that another class of instabilities, called microtearing modes, may be responsible for electron heat transport in the pedestal, and thereby play some role in determining the pedestal characteristics. Microtearing modes belong to a class of instabilities where a modification of the magnetic field line topology is induced at the ion Larmor radius scale. This leads to the formation of magnetic islands, which can enhance the electron heat transport. The stability of MTMs has been theoretically studied in the past showing that a slab current sheet is stable in the absence of collisions. In contrast, recent gyrokinetic simulations in toroidal geometry found unstable MTMs, even at low collisionality. The purpose of our work is to improve the MTM stability understanding by comparing new analytical theory to linear gyrokinetic simulations. More precisely, physical mechanisms (magnetic drift, electric potential) are progressively included in the analytical description to recover the numerical simulations results and to "reconcile" numerical MTM investigations with theory.

Self-Organization of Hot Plasmas

Author : Yu.N. Dnestrovskij
Publisher : Springer
ISBN 13 : 3319068024
Total Pages : 140 pages
Book Rating : 4.3/5 (19 download)

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Book Synopsis Self-Organization of Hot Plasmas by : Yu.N. Dnestrovskij

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.

Edge Plasma Studies in the Presence of Alfvén Wave and H-mode in the Phaedrus-T Tokamak

Author : Xin Wang
Publisher :
ISBN 13 :
Total Pages : 208 pages
Book Rating : 4.:/5 (89 download)

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Book Synopsis Edge Plasma Studies in the Presence of Alfvén Wave and H-mode in the Phaedrus-T Tokamak by : Xin Wang

Download or read book Edge Plasma Studies in the Presence of Alfvén Wave and H-mode in the Phaedrus-T Tokamak written by Xin Wang and published by . This book was released on 1997 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Energy and Water Development Appropriations for 2009

Author : United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water Development
Publisher :
ISBN 13 :
Total Pages : 1490 pages
Book Rating : 4.F/5 ( download)

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Book Synopsis Energy and Water Development Appropriations for 2009 by : United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water Development

Download or read book Energy and Water Development Appropriations for 2009 written by United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water Development and published by . This book was released on 2008 with total page 1490 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Scientific and Technical Aerospace Reports

Author :
Publisher :
ISBN 13 :
Total Pages : 704 pages
Book Rating : 4.:/5 (31 download)

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Book Synopsis Scientific and Technical Aerospace Reports by :

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Two Phase Flow, Phase Change and Numerical Modeling

Author : Amimul Ahsan
Publisher : BoD – Books on Demand
ISBN 13 : 9533075848
Total Pages : 600 pages
Book Rating : 4.5/5 (33 download)

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Book Synopsis Two Phase Flow, Phase Change and Numerical Modeling by : Amimul Ahsan

Download or read book Two Phase Flow, Phase Change and Numerical Modeling written by Amimul Ahsan and published by BoD – Books on Demand. This book was released on 2011-09-26 with total page 600 pages. Available in PDF, EPUB and Kindle. Book excerpt: The heat transfer and analysis on laser beam, evaporator coils, shell-and-tube condenser, two phase flow, nanofluids, complex fluids, and on phase change are significant issues in a design of wide range of industrial processes and devices. This book includes 25 advanced and revised contributions, and it covers mainly (1) numerical modeling of heat transfer, (2) two phase flow, (3) nanofluids, and (4) phase change. The first section introduces numerical modeling of heat transfer on particles in binary gas-solid fluidization bed, solidification phenomena, thermal approaches to laser damage, and temperature and velocity distribution. The second section covers density wave instability phenomena, gas and spray-water quenching, spray cooling, wettability effect, liquid film thickness, and thermosyphon loop. The third section includes nanofluids for heat transfer, nanofluids in minichannels, potential and engineering strategies on nanofluids, and heat transfer at nanoscale. The forth section presents time-dependent melting and deformation processes of phase change material (PCM), thermal energy storage tanks using PCM, phase change in deep CO2 injector, and thermal storage device of solar hot water system. The advanced idea and information described here will be fruitful for the readers to find a sustainable solution in an industrialized society.

Simulation of Edge-plasma Profiles and Turbulence Related to L-H Transitions in Tokamaks

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (683 download)

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Book Synopsis Simulation of Edge-plasma Profiles and Turbulence Related to L-H Transitions in Tokamaks by :

Download or read book Simulation of Edge-plasma Profiles and Turbulence Related to L-H Transitions in Tokamaks written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding plasma profile evolution and plasma turbulence are two important aspects of developing a predictive model for edge-plasma in tokamaks and other fusion-related devices. Here they describe results relevant to the L-H transition phenomena observed in tokamaks obtained from two simulations codes which emphasize the two aspects of the problem. UEDGE solves for the two-dimensional (2-D) profiles of a multi-species plasma and neutrals given some anomalous cross-field diffusion coefficients, and BOUT solves for the three-dimensional (3-D) turbulence that gives rise to the anomalous diffusion. These two codes are thus complementary in solving different aspects of the edge-plasma transport problem; ultimately, they want to couple the codes so that UEDGE uses BOUT's turbulence transport results, and BOUT uses UEDGE's plasma profiles with a fully automated iteration procedure. This goal is beyond the present paper; here they show how each aspect of the problem, i.e., profiles and turbulent transport, can contribute to L-H type transitions.

Electron Cyclotron Emission And Electron Cyclotron Heating (Ec12), Proceedings Of The 12th Joint Workshop

Author : Gerardo Giruzzi
Publisher : World Scientific
ISBN 13 : 9814487295
Total Pages : 613 pages
Book Rating : 4.8/5 (144 download)

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Book Synopsis Electron Cyclotron Emission And Electron Cyclotron Heating (Ec12), Proceedings Of The 12th Joint Workshop by : Gerardo Giruzzi

Download or read book Electron Cyclotron Emission And Electron Cyclotron Heating (Ec12), Proceedings Of The 12th Joint Workshop written by Gerardo Giruzzi and published by World Scientific. This book was released on 2003-02-21 with total page 613 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 12th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating (EC-12) was held in Aix-en-Provence (France) from May 13 to 16, 2002. This workshop was concerned with the interaction of electromagnetic waves and hot plasmas, a subject of great importance in the framework of research on controlled thermonuclear fusion. Using as a fuel a mixture of deuterium and tritium, which can be extracted from sea water, this is a very promising way to develop an intrinsically safe reactor. The workshop gathered approximately one hundred specialists in the production, use and theory of millimetre waves for heating and diagnostics of fusion plasmas.

Power Exhaust in Fusion Plasmas

Author : Wojciech Fundamenski
Publisher : Cambridge University Press
ISBN 13 : 0521851718
Total Pages : 445 pages
Book Rating : 4.5/5 (218 download)

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Book Synopsis Power Exhaust in Fusion Plasmas by : Wojciech Fundamenski

Download or read book Power Exhaust in Fusion Plasmas written by Wojciech Fundamenski and published by Cambridge University Press. This book was released on 2010 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: A complete and up-to-date summary of power exhaust in fusion plasmas, for academic researchers and graduate students in plasma physics.