Plasma Simulation Studies in the Ion Cyclotron Frequency Range PDF Download
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Author: Niels Fujio Otani
Publisher:
ISBN:
Category :
Languages : en
Pages : 480
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Author: Niels Fujio Otani
Publisher:
ISBN:
Category :
Languages : en
Pages : 480
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Author: T. Hellsten
Publisher:
ISBN:
Category :
Languages : en
Pages : 50
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Author: T. Hellsten
Publisher:
ISBN:
Category :
Languages : en
Pages : 30
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Book Description
Author: D. G. Lominadze
Publisher: Elsevier
ISBN: 1483280780
Category : Science
Languages : en
Pages : 219
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Book Description
Cyclotron Waves in Plasma is a four-chapter text that covers the basic physical concepts of the theory of cyclotron waves and cyclotron instabilities, brought about by the existence of steady or alternating plasma currents flowing perpendicular to the magnetic field. This book considers first a wide range of questions associated with the linear theory of cyclotron oscillations in equilibrium plasmas and in electron plasmas in metals and semiconductors. The next chapter deals with the parametric excitation of electron cyclotron oscillations in plasma in an alternating electric field. A chapter focuses on plasma turbulence, which results from the development of cyclotron instabilities. The last chapter discusses pertinent experimental data concerning cyclotron waves in plasma. The book is intended for specialists in plasma physics and a number of related fields, including the physics of the ionosphere, solar wind and, metals, as well as for students and teachers who are specializing in these subjects.
Author: Volodymyr Girka
Publisher: Springer
ISBN: 3030171159
Category : Science
Languages : en
Pages : 206
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Book Description
This book is the first of its kind devoted to surface waves propagating across an external static magnetic field at harmonics of the electron cyclotron frequency. Based on comprehensive theoretical studies carried out over the course of about forty years, it presents unique material on various characteristics of these transverse waves, namely, dispersion properties and their dependence on numerous design peculiarities of plasma waveguides; damping due to interaction with the plasma surface (the kinetic channel) and collisions between plasma particles (the Ohmic channel); interaction with flows of charged particles moving above the plasma surface; parametric excitation due to the effect of an external radiofrequency field; and their power transfer for sustaining gas discharges. Clarifying numerous complicated mathematical issues it is a valuable resource for postgraduate students and experts in plasma physics, electromagnetic waves, and the kinetic theory of plasmas.
Author: Dani Gallart Escolà
Publisher:
ISBN:
Category :
Languages : en
Pages : 141
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Book Description
Heating plasmas to a relevant fusion temperature is one of the key aspects of magnetically confined fusion plasmas. Radio frequency (RF) heating with electromagnetic waves in the ion cyclotron range of frequencies (ICRF) has been proven to be an efficient auxiliary method in present fusion devices such as tokamaks. Moreover, the International Thermonuclear Experimental Reactor (ITER) will be provided with ICRF antennas as one of the main heating mechanisms. For that, the study of different heating schemes to optimise the fusion performance is of utmost importance.During the 2015-2019 Joint European Torus (JET) campaigns many efforts have been devoted to the exploration of high-performance plasma scenarios envisaged for D-T operation in JET. Experiments in D, H and T are expected to lead in 2020 to the first experiments with 50%:50% D-T mixtures. These last campaigns at JET have been focused on enhancing the fusion performance of the baseline and hybrid scenarios with the final goal of improving ITER's future operation. This thesis reports on the modelling study of plasma heating through ICRF waves and NBI for recent experiments at JET with special emphasis on plasma performance.The modelling has been performed mainly with the ICRF code PION. Simulations are in excellent agreement with experimental results which proves the reliability of the results shown in this thesis. The assessment of the results offer an overview to understand and optimise plasma performance for high-performance hybrid discharges that were performed with D plasma and H minority. Impurity accumulation control with ICRF waves was found to be efficient only for a range of central resonance locations while impurity accumulation occurred for off-axis resonance. Contribution to temperature screening from fast ions was calculated to be negligible when finite orbit widths (FOW) are taken into account, as opposed to previous studies that did not take into account FOW. Small differences in H concentration have a large impact on power partition between H and D. The lower the H concentration the larger the power channeled to D which is shown to substantially enhance the D-D fusion rate. The study of a neutron record high-performance discharge shows high bulk ion heating and low H concentration as key ingredients for increased fusion performance.Of especial relevance for ITER is the study of the D-T prediction from high-performance discharges. This analysis compares two ICRF schemes, H and 3He minority. It is shown that 3He is a strong absorber and provides higher bulk ion heating as compared to H. However, ICRF fusion enhancement is computed to be larger in H, as this scheme has a stronger 2nd harmonic heating. In D-T, ICRF fusion enhancement is computed to be significantly lower with regards to D-D plasmas due to different fusion cross sections. Results in preparation of the T and D-T campaigns at JET show that the extrapolation from T to D-T plasmas is not straightforward. PION predicts the T density to have a large impact on the T velocity distribution function for the ITER relevant 2nd$ T harmonic heating scheme. Larger concentrations of T lead to higher bulk ion heating, therefore, it is expected D-T bulk ion heating to be lower.
Author: Ian G. Brown
Publisher:
ISBN:
Category : Magnetic mirrors
Languages : en
Pages : 48
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Book Description
Author: Andreas Keiling
Publisher: John Wiley & Sons
ISBN: 1119054958
Category : Science
Languages : en
Pages : 524
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Book Description
Low-frequency waves in space plasmas have been studied for several decades, and our knowledge gain has been incremental with several paradigm-changing leaps forward. In our solar system, such waves occur in the ionospheres and magnetospheres of planets, and around our Moon. They occur in the solar wind, and more recently, they have been confirmed in the Sun’s atmosphere as well. The goal of wave research is to understand their generation, their propagation, and their interaction with the surrounding plasma. Low-frequency Waves in Space Plasmas presents a concise and authoritative up-to-date look on where wave research stands: What have we learned in the last decade? What are unanswered questions? While in the past waves in different astrophysical plasmas have been largely treated in separate books, the unique feature of this monograph is that it covers waves in many plasma regions, including: Waves in geospace, including ionosphere and magnetosphere Waves in planetary magnetospheres Waves at the Moon Waves in the solar wind Waves in the solar atmosphere Because of the breadth of topics covered, this volume should appeal to a broad community of space scientists and students, and it should also be of interest to astronomers/astrophysicists who are studying space plasmas beyond our Solar System.
Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 1044
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Book Description
Author: Haruhiko Kohno
Publisher:
ISBN:
Category :
Languages : en
Pages : 191
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Book Description
Electromagnetic plasma waves in the ion cyclotron range of frequencies (ICRF) are routinely used in magnetic fusion experiments to heat plasmas and drive currents. However, many experiments have revealed that wave energy losses in the plasma edge and at the wall are significant, and detected that the acceleration of ions into the walls due to the formation of radio-frequency (RF) sheaths is one of the root causes of this problem. Since the RF-enhanced sheaths have many undesirable effects, such as impurity production and hot spot generation, a predictive numerical tool is required to quantitatively evaluate these effects with complicated boundary shapes of tokamaks taken into account. In this thesis the numerical code that solves self-consistent RF sheath-plasma interactions in the scrape-off layer for ICRF heating is developed based on a nonlinear finite element technique and is applied to various problems in the one-dimensional (1D) and two-dimensional (2D) domains corresponding to simplified models for the poloidal plane of a tokamak. The present code solves for plasma waves based on the cold plasma model subject to the sheath boundary condition, in which the most important physics that happens in the sheath is captured without using the field quantities in the sheath. Using the developed finite element code, several new properties of the RF sheath plasma interactions are discovered. First, it is found in the 1D domain that multiple roots can be present due to the resonance of the propagating slow wave and its nonlinear interaction with the sheath. Second, sheath-plasma waves are identified in a 2D slab geometry, and it is proved in conjunction with an electrostatic 2D sheath mode analysis that the sheath-plasma wave only appears in the vicinity of the sheath surface if the plasma density is greater than the lower hybrid density, and its wavelength depends on various parameters. Third, as a consequence of the self-consistent interaction between the propagating slow wave and the sheath, it is shown that the electric field distribution pattern in the plasma smoothly varies along the magnetic field lines between the conducting-wall and quasi-insulating limits. In the numerical analysis employing the 2D domain whose scale is equivalent to the Alcator C-Mod device, it is demonstrated that the calculated sheath potential can reach the order of kV, which is sufficient to yield enhanced sputtering at the wall. In addition, it is shown that the sheath potential in the close vicinity of the antenna current strap can be insensitive to the direction of the background magnetic field in the RF sheath dominated regime. Further, it is found from a series of nonlinear calculations that the sheath potential sensitively varies depending on the plasma density and electron temperature, which is consistent with the scaling derived from the Child-Langmuir law and the definition of the RF sheath potential. Lastly, a new finite element approach, which is named the finite element wave-packet method, is developed for the purpose of solving for multiscale plasma waves in the tokamak poloidal plane accurately with reasonable computational cost. This method is established by combining the advantages of the finite element and spectral methods, so that important properties in the finite element method, such as the sparsity of the global matrix and the ease in satisfying the boundary conditions, are retained. The present scheme is applied to some illustrative 1D multiscale problems, and its accuracy improvement is demonstrated through comparisons with the conventional finite element method.
