Author: Canh Ngoc Nguyen
Publisher:
ISBN:
Category : Tokamaks
Languages : en
Pages : 372
Book Description
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.
Predictive Integrated Modeling of Low Aspect Ratio Tokamaks and Large Scale Instabilities in Tokamaks
Author: Canh Ngoc Nguyen
Publisher:
ISBN:
Category : Tokamaks
Languages : en
Pages : 372
Book Description
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.
Publisher:
ISBN:
Category : Tokamaks
Languages : en
Pages : 372
Book Description
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.
Dissertation Abstracts International
Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 754
Book Description
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 754
Book Description
Autograph Letter Signed from J.Y. Savage, New York City, to Augustin Daly
Author: J. Y. Savage
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
On letterhead of the New York citizen and round table.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
On letterhead of the New York citizen and round table.
Stability of High Beta Large Aspect Ratio Tokamaks
Author: Steven C. Cowley
Publisher:
ISBN:
Category :
Languages : en
Pages : 26
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 26
Book Description
Access to the Second Stability Region in a High Shear, Low Aspect Ratio Tokamak
Author: Michael J. Gerver
Publisher:
ISBN:
Category :
Languages : en
Pages : 72
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 72
Book Description
Global Stability Study of the Ultra Low Aspect Ratio Tokamak, ULART.
Author: Masaaki Yamada
Publisher:
ISBN:
Category : Magnetohydrodynamic instabilities
Languages : en
Pages : 16
Book Description
Publisher:
ISBN:
Category : Magnetohydrodynamic instabilities
Languages : en
Pages : 16
Book Description
Large Scale Instabilities in Tokamaks
Author: Alexander William Morris
Publisher:
ISBN:
Category : Magnetohydrodynamic instabilities
Languages : en
Pages : 0
Book Description
Publisher:
ISBN:
Category : Magnetohydrodynamic instabilities
Languages : en
Pages : 0
Book Description
Tokamaks
Author: John Wesson
Publisher: Oxford University Press, USA
ISBN:
Category : Science
Languages : en
Pages : 704
Book Description
The tokamak is the principal tool in controlled fusion research. This book serves as an introduction to the subject and a basic reference for theory, definitions, equations, and experimental results. This second edition covers advances in the field as well as the extensive experimental progress in the ten years since the first edition was published.
Publisher: Oxford University Press, USA
ISBN:
Category : Science
Languages : en
Pages : 704
Book Description
The tokamak is the principal tool in controlled fusion research. This book serves as an introduction to the subject and a basic reference for theory, definitions, equations, and experimental results. This second edition covers advances in the field as well as the extensive experimental progress in the ten years since the first edition was published.
Large Scale Instabilities in Tokamaks
Author: Alexander William Morris
Publisher:
ISBN:
Category : Tokamaks
Languages : en
Pages : 500
Book Description
Publisher:
ISBN:
Category : Tokamaks
Languages : en
Pages : 500
Book Description
A Low-field Low-aspect-ratio Tokamak
Author: Juda Leon Shohet
Publisher:
ISBN:
Category : Tokamaks
Languages : en
Pages : 30
Book Description
Publisher:
ISBN:
Category : Tokamaks
Languages : en
Pages : 30
Book Description