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Author: Martin Greenwald Publisher: ISBN: Category : Languages : en Pages : 174
Book Description
(cont.) This link unified L-mode and H-mode and established a strong connection between local and global transport. Further work on the role of critical gradient lengths and marginal stability lent quantitative support to the ITG theories for ion transport and have helped elucidate nonlinear saturation mechanisms for the turbulence. Local transport studies demonstrated connections between transport channels, with energy, particle and momentum transport varying across regimes in similar ways. Experiments carried out in collaboration with the DIII-D, ASDEX-U and JET groups confirmed the dimensionless scaling approach over the widest available range in machine sizes. These studies suggest that plasma physics is the dominant influence on transport in the core and pedestal for standard L- and H-mode discharges. Dimensionless scaling experiments have shown a strong improvement in confinement with the normalized gyro-size (1/p*). Confinement was found to be Bohm-like in L-mode and gyro-Bohm-like in H-mode. These experiments also showed a strong degradation in confinement with collisionality. Other articles in this issue discuss impurity transport, momentum transport, H-mode pedestal and threshold physics and internal transport barrier regimes.
Author: Martin Greenwald Publisher: ISBN: Category : Languages : en Pages : 174
Book Description
(cont.) This link unified L-mode and H-mode and established a strong connection between local and global transport. Further work on the role of critical gradient lengths and marginal stability lent quantitative support to the ITG theories for ion transport and have helped elucidate nonlinear saturation mechanisms for the turbulence. Local transport studies demonstrated connections between transport channels, with energy, particle and momentum transport varying across regimes in similar ways. Experiments carried out in collaboration with the DIII-D, ASDEX-U and JET groups confirmed the dimensionless scaling approach over the widest available range in machine sizes. These studies suggest that plasma physics is the dominant influence on transport in the core and pedestal for standard L- and H-mode discharges. Dimensionless scaling experiments have shown a strong improvement in confinement with the normalized gyro-size (1/p*). Confinement was found to be Bohm-like in L-mode and gyro-Bohm-like in H-mode. These experiments also showed a strong degradation in confinement with collisionality. Other articles in this issue discuss impurity transport, momentum transport, H-mode pedestal and threshold physics and internal transport barrier regimes.
Author: Choongki Sung Publisher: ISBN: Category : Languages : en Pages : 478
Book Description
The comprehensive analysis was performed to study turbulent transport in Alcator CMod plasmas in this thesis. A new Correlation Electron Cyclotron Emission (CECE) diagnostic was designed and installed as a part of this thesis work. Using this diagnostic, we measured local T fluctuations in r/a >/~ 0.75 in C-Mod for the first time. This thesis work provided new information about the Ohmic confinement transition, from the linear to the saturated confinement regime with the increase in average density. It was found that Te fluctuations near the edge (r/a0~.85) tend to decrease across the Ohmic confinement transition. Although the Ohmic confinement transition has been considered predominantly as a result of the linear turbulence mode transition, we found no changes in the dominant turbulence mode across this transition via gyrokinetic analysis using the code, GYRO. The GYRO simulations performed near the edge reproduce experimental ion heat flux and Te fluctuations, but electron heat flux was under-predicted. Considering that both ion heat flux and the T fluctuations mainly come from ion scale turbulence, the under-prediction of electron heat flux suggests the importance of electron scale turbulence. Intrinsic rotation reversals in C-Mod plasmas were studied in this thesis. Similar changes in electron temperature fluctuations, the reduction of Te fluctuations near the edge, were observed across RF rotation reversals and Ohmic rotation reversals. The gyrokinetic and self-similarity analyses also showed similarities between rotation reversals in Ohmic and RF heated discharges. These observations suggest that the physics of Ohmic confinement transition and the rotation reversal can be applied to the physics of rotation reversal in RF heated discharges. This thesis also found the reduction of Te fluctuations inside pedestal region with the transition from low to high energy confinement regime, which indicates the changes in core turbulence are correlated with the global energy confinement.
Author: George Neilson Publisher: Woodhead Publishing ISBN: 0081003269 Category : Science Languages : en Pages : 634
Book Description
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
Author: Jerry Wayne Hughes Publisher: ISBN: Category : Languages : en Pages : 104
Book Description
H-mode research on Alcator C-Mod is described, with a focus on the edge transport barrier (ETB). ETB pedestals are characterized using several diagnostics, leading to a thorough description of profile structure in H-mode. L-H transition criteria are discussed, along with the fast evolution of the pedestal following the L-H transition. H-mode regimes are described in terms of their edge transport characteristics and the local edge parameters favoring each. Empirical scalings of the pedestal with operational parameters are found, helping to illuminate physics governing the pedestal structure, and the relationship between edge transport and global confinement is discussed. Dimensionless comparisons between discharges on different tokamaks are discussed. Finally, ongoing work and directions for the future are described.
Author: C Wendell Horton, Jr Publisher: World Scientific ISBN: 9814678686 Category : Science Languages : en Pages : 248
Book Description
The promise of a vast and clean source of thermal power drove physics research for over fifty years and has finally come to collimation with the international consortium led by the European Union and Japan, with an agreement from seven countries to build a definitive test of fusion power in ITER. It happened because scientists since the Manhattan project have envisioned controlled nuclear fusion in obtaining energy with no carbon dioxide emissions and no toxic nuclear waste products.This large toroidal magnetic confinement ITER machine is described from confinement process to advanced physics of plasma-wall interactions, where pulses erupt from core plasma blistering the machine walls. Emissions from the walls reduce the core temperature which must remain ten times hotter than the 15 million degree core solar temperature to maintain ITER fusion power. The huge temperature gradient from core to wall that drives intense plasma turbulence is described in detail.Also explained are the methods designed to limit the growth of small magnetic islands, the growth of edge localized plasma plumes and the solid state physics limits of the stainless steel walls of the confinement vessel from the burning plasma. Designs of the wall coatings and the special 'exhaust pipe' for spent hot plasma are provided in two chapters. And the issues associated with high-energy neutrons — about 10 times higher than in fission reactions — and how they are managed in ITER, are detailed.
Author: Eun-jin Kim Publisher: MDPI ISBN: 3039211080 Category : Mathematics Languages : en Pages : 300
Book Description
This book is a printed edition of the Special Issue Intermittency and Self-Organisation in Turbulence and Statistical Mechanics that was published in Entropy
Author: United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water Development Publisher: ISBN: Category : Languages : en Pages : 3118
Author: United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water Development Publisher: ISBN: Category : Energy development Languages : en Pages : 3046
Author: Martin Greenwald
Author: Martin Greenwald
Author: Choongki Sung
Author: George Neilson
Author: Jerry Wayne Hughes
Author: 
Author: C Wendell Horton, Jr
Author: Eun-jin Kim
Author: United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water Development
Author: United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water Development
Author: