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 Lower Hybrid Current Drive Experiments in the HT 7 Tokamak written by Zhongyong Chen and published by Nova Novinka. This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The achievement of steady state operation and long pulse is one of the major challenges in the tokamak plasmas. One of the most effective means to sustain tokamak steady state operation is non-inductive current drive (NICD) by lower hybrid (LH) wave. Lower hybrid current drive (LHCD) as an effective NICD tool has been demonstrated in many tokamaks. LHCD is used to modify the plasma current profile to improve the MHD stability, or used in conjunction with ion Bernstein wave (IBW) to achieve high performance discharge. The achievement of high current drive efficiency is of primary importance since it determines the required power that must be recycled to sustain the plasma current. This book discusses the lower-hybrid current drive experiences currently being done in regards to HT-7 tokamaks.

Download or read book Steady state Current Drive in Tokamaks Workshop Summary written by United States. Department of Energy. Division of Magnetic Confinement Systems and published by . This book was released on 1979 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Frontiers in Fusion Research II written by Mitsuru Kikuchi and published by Springer. This book was released on 2015-09-03 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews recent progress in our understanding of tokamak physics related to steady state operation, and addresses the scientific feasibility of a steady state tokamak fusion power system. It covers the physical principles behind continuous tokamak operation and details the challenges remaining and new lines of research towards the realization of such a system. Following a short introduction to tokamak physics and the fundamentals of steady state operation, later chapters cover parallel and perpendicular transport in tokamaks, MHD instabilities in advanced tokamak regimes, control issues, and SOL and divertor plasmas. A final chapter reviews key enabling technologies for steady state reactors, including negative ion source and NBI systems, Gyrotron and ECRF systems, superconductor and magnet systems, and structural materials for reactors. The tokamak has demonstrated an excellent plasma confinement capability with its symmetry, but has an intrinsic drawback with its pulsed operation with inductive operation. Efforts have been made over the last 20 years to realize steady state operation, most promisingly utilizing bootstrap current. Frontiers in Fusion Research II: Introduction to Modern Tokamak Physics will be of interest to graduate students and researchers involved in all aspects of tokamak science and technology.