Download or read book Towards Integrated Control of Tokamak Plasmas Physics based Control of Neoclassical Tearing Modes in the TCV Tokamak written by Mengdi Kong and published by . This book was released on 2020 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mots-clés de l'auteur: neoclassical tearing modes (NTMs) ; modified Rutherford equation (MRE) ; triggerless NTMs ; NTM stabilization ; NTM prevention ; integrated control ; ITER ; DEMO.
Download or read book Magnetic Control of Tokamak Plasmas written by Marco Ariola and published by Springer. This book was released on 2016-02-23 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a complete treatment of work done to resolve the problems of position-, current-, and shape-control of plasma in tokamak-type (toroidal) devices being studied as a potential means of commercial energy production by nuclear fusion. Modelling and control are both detailed, allowing non-expert readers to understand the control problem. Starting from the magneto-hydro-dynamic equations, all the steps needed for the derivation of plasma state-space models are enumerated with frequent recall of the basic concepts of electromagnetics. The control problem is then described, beginning with the control of current and position—vertical and radial—control and progressing to the more challenging shape control. The solutions proposed vary from simple PIDs to more sophisticated MIMO controllers. The second edition of Magnetic Control of Tokamak Plasmas contains numerous updates and a substantial amount of completely new material covering areas such as: • modelling and control of resistive wall modes—the most important non-axisimmetric mode; • the isoflux approach for shape control; • a general approach for the control of limiter plasmas; • the use of inner vessel coils for vertical stabilization; and • significantly enhanced treatment of plasma-shape control at JET, including experimental results and introducing a method implemented for operation in the presence of current saturations. Whenever possible, coverage of the various topics is rounded out with experimental results obtained on currently existing tokamaks. The book also includes a presentation of the typical actuators and sensors used for control purposes in tokamaks. Some mathematical details are given in the appendices for the interested reader. The ideas formulated in this monograph will be of great practical help to control engineers, academic researchers and graduate students working directly with problems related to the control of nuclear fusion. They will also stimulate control researchers interested more generally in the advanced applications of the discipline. Advances in Industrial Control aims to report and encourage the transfer of technology in control engineering. The rapid development of control technology has an impact on all areas of the control discipline. The series offers an opportunity for researchers to present an extended exposition of new work in all aspects of industrial control.
Download or read book Theory of Tokamak Plasmas written by R.B. White and published by North Holland. This book was released on 1989-08-04 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is a graduate textbook on tokamak physics, designed to provide a basic introduction to plasma equilibrium, particle orbits, transport, and those ideal and resistive magnetohydrodynamic instabilities which dominate the behavior of a tokamak discharge, and to develop the mathematical methods necessary for their theoretical analysis.
Download or read book Safety Factor Profile Control in a Tokamak written by Federico Bribiesca Argomedo and published by Springer Science & Business Media. This book was released on 2013-11-08 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: Control of the Safety Factor Profile in a Tokamak uses Lyapunov techniques to address a challenging problem for which even the simplest physically relevant models are represented by nonlinear, time-dependent, partial differential equations (PDEs). This is because of the spatiotemporal dynamics of transport phenomena (magnetic flux, heat, densities, etc.) in the anisotropic plasma medium. Robustness considerations are ubiquitous in the analysis and control design since direct measurements on the magnetic flux are impossible (its estimation relies on virtual sensors) and large uncertainties remain in the coupling between the plasma particles and the radio-frequency waves (distributed inputs). The Brief begins with a presentation of the reference dynamical model and continues by developing a Lyapunov function for the discretized system (in a polytopic linear-parameter-varying formulation). The limitations of this finite-dimensional approach motivate new developments in the infinite-dimensional framework. The text then tackles the construction of an input-to-state-stability Lyapunov function for the infinite-dimensional system that handles the medium anisotropy and provides a common basis for analytical robustness results. This function is used as a control-Lyapunov function and allows the amplitude and nonlinear shape constraints in the control action to be dealt with. Finally, the Brief addresses important application- and implementation-specific concerns. In particular, the coupling of the PDE and the finite-dimensional subsystem representing the evolution of the boundary condition (magnetic coils) and the introduction of profile-reconstruction delays in the control loop (induced by solving a 2-D inverse problem for computing the magnetic flux) is analyzed. Simulation results are presented for various operation scenarios on Tore Supra (simulated with METIS) and on TCV (simulated with RAPTOR). Control of the Safety Factor Profile in a Tokamak will be of interest to both academic and industrially-based researchers interested in nuclear energy and plasma-containment control systems, and graduate students in nuclear and control engineering.
Download or read book Tearing Mode Dynamics in Tokamak Plasmhb written by FITZPATRICK and published by IOP Series in Plasma Physics. This book was released on 2024-07-31 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This comprehensive research and reference text aims to outline a realistic, comprehensive, self-consistent, analytic theory of tearing mode dynamics in tokamak plasmas.
Download or read book Control of Coupled Transport in Tokamak Plasmas written by Bojan Mavkov and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this thesis is to propose new methods for analysis and control of partial differential equations that describe the coupling between the transport models of the electron pressure (density multiplied by the temperature) and the magnetic flux in the tokamak plasma. The coupled system is presented by two1D resistive diffusion equations. In this thesis two kinds of control models are obtained. The first is a first-principle driven model and the second one is the data-driven model obtained using system identification techniques. The control design is based on an infinite dimensional setting using Lyapunov analysis. Composite control is designed using singular perturbation theory to divide the fast from the slow component. All the theoretical work is implemented and benchmarked in advanced physics based on simulations using plasma simulator dor DIII-D, ITER and TCV tokamaks.
Download or read book Stabilization of Neoclassical Tearing Modes in Tokamak Fusion Plasmas Via Extremum Seeking written by William P. Wehner and published by . This book was released on 2009 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: The neoclassical tearing mode (NTM) instability produces magnetic islands in tokamak plasmas that can degrade confinement and lead to plasma disruptions. NTMs are driven by a lack of bootstrap current inside the magnetic island where the pressure profile is flattened. Suppression of these islands is necessary for sustained energy confinement and efficient operation in tokamak magnetic-fusion reactors. Compensating for the lack of bootstrap current by an Electron Cyclotron Current Drive (ECCD) has been proved experimentally as an effective method to stabilize NTMs. The effectiveness of this method is limited in practice by the uncertainties in the width of the island, the relative position between the island and the EC beam, and the EC power threshold for NTM stabilization. Heuristic Search and Suppress algorithms have been proposed and shown effective to improve the alignment of the EC beam with the island by just using an estimate of the island width. Making use of this estimate, a real-time, non-model-based, extremum-seeking optimization algorithm is proposed for EC beam steering and modulation in order to minimize the island-beam misalignment and the time (control energy) required for NTM stabilization. The efficiency of the proposed method is compared with traditional search and suppress algorithms. It is shown that the Extremum Seeking method has the potential of reducing NTM suppression times. In addition, it is shown that the Extremum Seeking method has the ability of modulating simultaneously other parameters beyond island-beam alignment that improve the effectiveness of the ECCD such as modulation duty-cycle and the phase mismatch between the ECCD and island O-point.
Download or read book Real Time Control of Tokamak Plasmas from Control of Physics to Physics Based Control written by Federico Alberto Alfredo Felici and published by . This book was released on 2011 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Neoclassical Tearing Modes in a Tokamak written by T. S. Hahm and published by . This book was released on 1988 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Modelling Neoclassical Tearing Modes in Tokamak Plasmas written by Aleksandra Dudkovskaia and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book HIGH PERFORMANCE ADVANCED TOKAMAK REGIMES FOR NEXT STEP EXPERIMENTS written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: OAK-B135 Advanced Tokamak (AT) research in DIII-D seeks to provide a scientific basis for steady-state high performance operation in future devices. These regimes require high toroidal beta to maximize fusion output and poloidal beta to maximize the self-driven bootstrap current. Achieving these conditions requires integrated, simultaneous control of the current and pressure profiles, and active magnetohydrodynamic (MHD) stability control. The building blocks for AT operation are in hand. Resistive wall mode stabilization via plasma rotation and active feedback with non-axisymmetric coils allows routine operation above the no-wall beta limit. Neoclassical tearing modes are stabilized by active feedback control of localized electron cyclotron current drive (ECCD). Plasma shaping and profile control provide further improvements. Under these conditions, bootstrap supplies most of the current. Steady-state operation requires replacing the remaining Ohmic current, mostly located near the half-radius, with noninductive external sources. In DIII-D this current is provided by ECCD, and nearly stationary AT discharges have been sustained with little remaining Ohmic current. Fast wave current drive is being developed to control the central magnetic shear. Density control, with divertor cryopumps, of AT discharges with edge localized moding (ELMing) H-mode edges facilitates high current drive efficiency at reactor relevant collisionalities. A sophisticated plasma control system allows integrated control of these elements. Close coupling between modeling and experiment is key to understanding the separate elements, their complex nonlinear interactions, and their integration into self-consistent high performance scenarios. Progress on this development, and its implications for next-step devices, will be illustrated by results of recent experiment and simulation efforts.
Download or read book Simulation of Plasma Evolution and Shape Control in the TCV Tokamak written by F. B. Marcus and published by . This book was released on 1988 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics model based Optimization and Feedback Control of the Current Profile Dynamics in Fusion Tokamak Reactors written by Justin E. Barton and published by . This book was released on 2015 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Examples of the performance of the controllers in simulations (DIII-D, ITER, and TCV tokamaks) and DIII-D experiments are presented to illustrate the potential and versatility of the employed control methodology. The DIII-D experimental tests demonstrate the potential physics-model-based profile control has to provide a systematic approach for the development and robust sustainment of advanced scenarios. The ITER simulations demonstrate the ability to drive the current profile to a stationary target while simultaneously modulating the amount of fusion power that is generated. Finally, the TCV simulations demonstrate the ability to drive the current and electron temperature profiles to a self consistent target, as well as to maintain the current profile in a stationary condition while simultaneously modulating the electron temperature profile between equilibrium points.
Download or read book ADVANCED TOKAMAK OPERATION USING THE DIII D PLASMA CONTROL SYSTEM written by and published by . This book was released on 2002 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: A271 ADVANCED TOKAMAK OPERATION USING THE DIII-D PLASMA CONTROL SYSTEM. The principal focus of experimental operations in the DIII-D tokamak is the advanced tokamak (AT) regime to achieve, which requires highly integrated and flexible plasma control. In a high performance advanced tokamak, accurate regulation of the plasma boundary, internal profiles, pumping, fueling, and heating must be well coordinated with MHD control action to stabilize such instabilities as tearing modes and resistive wall modes. Sophisticated monitors of the operational regime must provide detection of off-normal conditions and trigger appropriate safety responses with acceptable levels of reliability. Many of these capabilities are presently implemented in the DIII-D plasma control system (PCS), and are now in frequent or routine operational use. The present work describes recent development, implementation, and operational experience with AT regime control elements for equilibrium control, MHD suppression, and off-normal event detection and response.
Download or read book Advanced Tokamak Stability Theory written by Linjin Zheng and published by Morgan & Claypool Publishers. This book was released on 2014-04-01 with total page 156 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the advanced stability theories for magnetically confined fusion plasmas, especially in tokamaks. As the fusion plasma sciences advance, the gap between the textbooks and cutting-edge researches gradually develops. This book fills in
Download or read book Neoclassical Tearing Modes in a Tokamak written by and published by . This book was released on 1988 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Linear tearing instability is studied in the banana collisionality regime in tokamak geometry. Neoclassical effects produce significant modifications of Ohm's law and the vorticity equation so that the growth rate of tearing modes driven by .delta.' is dramatically reduced compared to the usual resistive MHD value. Consequences of this result, regarding the presence of pressure-gradient-driven neoclassical resistive interchange instabilities and the evolution of magnetic islands in the Rutherford regime, are discussed. 10 refs.
