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Review Of Plasma Heating By Waves In The Ion Cyclotron Range Of Frequencies
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Book Synopsis Review of Plasma Heating by Waves in the Ion-cyclotron Range of Frequencies by :
Download or read book Review of Plasma Heating by Waves in the Ion-cyclotron Range of Frequencies written by and published by . This book was released on 1978 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Three aspects of wave heating in the Ion-Cyclotron Range of Frequencies are reviewed. First, the many interesting physics phenomena are outlined which occur in this frequency regime and how they can be profitably utilized in tokamak and other heating experiments is indicated. Second, the key current theoretical problems are enumerated. Thirdly, how the ICRF program for the PLT tokamak can address most of the physics questions is shown.
Book Synopsis Radiofrequency Heating of Plasmas, by : R. A. Cairns
Download or read book Radiofrequency Heating of Plasmas, written by R. A. Cairns and published by CRC Press. This book was released on 1991 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cross and Manheimer/Lashmore-Davies sell steadily in the export market - potential for Cairns here. This book provides a concise introduction to the basic physics of radiofrequency heating. Most existing literature on the subject is at the research level, aimed at specialists in the field. It provides a survey of theoretical and experimental results with a large number of references to help the reader wishing for more detail. Provides a concise and readable account/ Basic physical principles are emphasised and more complicated mathematical ideas are explained in outline. Radiofrequency current drive is discussed in detail. "One criticsm may be lack of detail. I have deliberatly avoided including a lot of mathematical and experimental detail in order to keep the book short and to concentrate on the essential ideas. Enough references are given to lead anyone wishing more detail to the appropriate literature" - comment from the author? Export Market: Japan, USA, CERN, all important centres for fusion research Tokamaks - supercolliders for particle acceleration - particles are bombarded by extremely powerful lasers the beams of which are split many times through kms of piping - massive structurees largest currently in Japan but also important structure in US.
Book Synopsis Computational Analysis of Ion Cyclotron Resonance Frequency Heating for JET Experiments by : Dani Gallart Escolà
Download or read book Computational Analysis of Ion Cyclotron Resonance Frequency Heating for JET Experiments written by Dani Gallart Escolà and published by . This book was released on 2020 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Radio Frequency Heating in the Ion-cyclotron Range of Frequencies by : Donald G. Swanson
Download or read book Radio Frequency Heating in the Ion-cyclotron Range of Frequencies written by Donald G. Swanson and published by . This book was released on 1985 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Plasma Heating in Stellarators by Radio Frequency Electromagnetic Waves at the Fundamental Ion Cyclotron Resonance by : Vladimir Svidzinski
Download or read book Plasma Heating in Stellarators by Radio Frequency Electromagnetic Waves at the Fundamental Ion Cyclotron Resonance written by Vladimir Svidzinski and published by . This book was released on 1998 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ion Cyclotron Range of Frequencies Heating of Plasma with Small Impurity Production by :
Download or read book Ion Cyclotron Range of Frequencies Heating of Plasma with Small Impurity Production written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma including plasma ions is magnetically confined by a magnetic field. The plasma has a defined outer surface and is intersected by resonance surfaces of respective common ion cyclotron frequency of a predetermined species of plasma ions moving in the magnetic field. A radio frequency source provides radio frequency power at a radio frequency corresponding to the ion cyclotron frequency of the predetermined species of plasma ions moving in the field at a respective said resonance surface. RF launchers coupled to the radio frequency source radiate radio frequency energy at the resonance frequency onto the respective resonance surface within the plasma from a plurality of locations located outside the plasma at such respective distances from the intersections of the respective resonance surface and the defined outer surface and at such relative phases that the resulting interference pattern provides substantially null net radio frequency energy over regions near and including substantial portions of the intersections relative to the radio frequency energy provided thereby at other portions of the respective resonance surface within the plasma.
Book Synopsis PLT Ion Cyclotron Range of Frequencies Heating Program by :
Download or read book PLT Ion Cyclotron Range of Frequencies Heating Program written by and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurements of energetic ions, impurity influx, recycling, and Bernstein waves generated in the plasma core are described for ICRF heating in PLT. Such measurements are being used for several launchers in order to optimize rf power deposition and discharge conditions. Preparations are underway to extend operation to higher rf power levels (approx. 5 MW) for the best attainable PLT conditions to permit more reactor-relevant extrapolations.
Book Synopsis Computational Analysis of Ion Cyclotron Resonance Frequency Heating for DEMO by : Dani Gallart Escolà
Download or read book Computational Analysis of Ion Cyclotron Resonance Frequency Heating for DEMO written by Dani Gallart Escolà and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ion cyclotron resonance frequency heating (ICRH) is one of the most important mechanisms to heat fusion plasma. The magnetic field generated by the magnetic coils forces ions to follow a cyclotron trajectory around the magnetic field lines due to the Lorentz force. Therefore, ions revolve around the magnetic field lines in a determined frequency, the so called ion cyclotron frequency. ICRH is based on launching electromagnetic waves from the low-field side in such a way that their frequency matches the one from ions cyclotron frequency. When both frequencies match, another effect begins to occur, the wave-particle interaction. At this point, ions start damping the wave by absorbing its energy. This effect modifies the distribution function of ions which develops a tail in the high energy region. The fast ions produced by the energy absorption from the electromagnetic waves play an important role in heating the bulk plasma. Therefore, it is crucial to know how the energy of the wave is distributed among ions and electrons, and how the fast ions produced deliver their energy to the other particles, ions and electrons. This Msc thesis is a first computational assessment of bulk plasma heating for DEMO. The DEMOnstration power plant is a proposed nuclear fusion power plant that is expected to be built after the experimental reactor ITER. It will be the first fusion reactor to produce electrical energy. Its parameters and scope are still not fixed yet, a few different yet similar designs exist. However, the physical dimensions and energy output in DEMO are much bigger than that of ITER. In fact, DEMO's 2 to 4 gigawatts of fusion power will be in the scale of the modern electric power plants. In this sense, the analysis here presented, takes into account the evolution of the fast ions and assesses their behavior at DEMO. The ICRH scenarios studied are the second harmonic tritium with and without 3He in D-T plasma as they are regarded as the most promising ICRH scenarios. Plasma parameters, as temperature T and electron density ne, are scanned in order to obtain the behavior of the fast ions. A DEMO design point which has been used to perform deeper analysis for a determined case has been established at T = 30 keV , ne = 1.2 · 1020 m−3. The analysis has been carried out using the PION code. PION has been extensively benchmarked against JET results. It is able to solve the evolution in time of the distribution function and to compute the absorption of the electromagnetic wave. This problem must be solved self-consistently. PION simulations consist in a number of time steps. First of all, for each time step, the power absorbed is calculated. This information is then used for computing the distribution function with a Fokker-Planck model, which will be used to compute the absorption power at the beginning of the next time step. This process is repeated iteratively until convergence is reached. The results obtained in this work are two: i) the bulk ion heating and ii) fast ion parameters. We have noticed that by placing the resonance region slightly closer to the outer side the bulk ion heating is improved in both scenarios by reducing the direct electron damping. The values for bulk ion heating of a 100 MW electromagnetic wave launch are 55.84 MW for a plasma with 3% of 3He and 43.00 MW for a plasma without 3He. The plasma without the 3He dilution shows a higher reaction rate and also its fast ions are considerably more energetic. So, as the minority heating scenario has an enhanced bulk ion heating, the second harmonic tritium scenario presents two advantages, firstly that no 3He is required and secondly that there is no 3He dilution.
Book Synopsis Numerical Analysis of Radio-frequency Sheath-plasma Interactions in the Ion Cyclotron Range of Frequencies by : Haruhiko Kohno
Download or read book Numerical Analysis of Radio-frequency Sheath-plasma Interactions in the Ion Cyclotron Range of Frequencies written by Haruhiko Kohno and published by . This book was released on 2011 with total page 191 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Main Challenges of Heating Plasma with Waves at the Ion Cyclotron Resonance Frequency (ICRF) by : Guillaume Urbanczyk
Download or read book Main Challenges of Heating Plasma with Waves at the Ion Cyclotron Resonance Frequency (ICRF) written by Guillaume Urbanczyk and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Of all the techniques used for heating plasmas in fusion devices, waves in the Ion Cyclotron Resonance Frequency (ICRF ,ào MHz) continue to be exceptionally advantageous and unique insofar as it enables to deposit of power directly on ions in the core, significantly enhancing fast ion population together with fusion reaction products. However, because of the multiple inherent challenges,Äîsuch as matching robustness, antenna design, wave coupling efficiency, wave propagation, wave absorption, and plasma surface interactions due to radiofrequency (RF) sheath excitation,ÄîICRF is often one of the most complex heating systems to implement successfully. This chapter provides a brief introduction of these challenges and their respective underlying physics, together with examples of both simulations and experimental results from various tokamaks around the world. Finally, ICRF advantages and applications on present and future devices and perspectives of technological solutions are discussed and summarized.
Book Synopsis Wave Heating and Current Drive in Plasmas by : Victor L. Granatstein
Download or read book Wave Heating and Current Drive in Plasmas written by Victor L. Granatstein and published by CRC Press. This book was released on 1985 with total page 524 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ion Cyclotron Range of Frequencies Mode Conversion Electron Heating in Deuterium-hydrogen Plasmas in the Alcator C-Mod Tokamak by : Yijun Lin
Download or read book Ion Cyclotron Range of Frequencies Mode Conversion Electron Heating in Deuterium-hydrogen Plasmas in the Alcator C-Mod Tokamak written by Yijun Lin and published by . This book was released on 2003 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Localized direct electron heating by mode-converted ion cyclotron range of frequencies (ICRF) waves in D(H) tokamak plasmas has been clearly observed for the first time in Alcator C-Mod. Both on- and off-axis (high field side) mode conversion electron heating (MCEH) have been observed. The MCEH profile was obtained from a break in slope analysis of electron temperature signals in the presence of rf (radio frequency) shut-off. The temperature was measured by a 32-channel high spatial resolution (7 mm) 2nd harmonic heterodyne electron cyclotron emission (ECE) system. The experimental profiles were compared with the predictions from a toroidal full-wave ICRF code TORIC. Using the hydrogen concentration measured by a high-resolution optical spectrometer, TORIC predictions were shown qualitatively in agreement with the experimental results for both on- and off-axis MC cases. From the simulations, the electron heating from mode converted ion cyclotron wave (ICW) and ion Bernstein wave (IBW) is examined.
Book Synopsis Plasma heating near the ion cyclotron frequency and its harmonics by : Reginald Wayne Clark
Download or read book Plasma heating near the ion cyclotron frequency and its harmonics written by Reginald Wayne Clark and published by . This book was released on 1971 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: Additions have been made to the theory of the Quasi Ion Bernstein modes which propagate for wave frequencies near the harmonics of the ion cyclotron frequency, and experience ion cyclotron damping as the harmonic resonances are approached. The effects of collisions and electron Landau damping have been included, and group velocity calculations have been performed. When the effects of collisions are included, the theory predicts strong collisional damping in high density, low temperature collision dominated plasmas, whereas the original theory predicted wave propagation in the absence of collisions. (Author).
Book Synopsis High Power Heating in the Ion Cyclotron Range of Frequencies in the Wisconsin Tokapole II. by :
Download or read book High Power Heating in the Ion Cyclotron Range of Frequencies in the Wisconsin Tokapole II. written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Fast wave heating at the second, third, and fourth harmonics of the ion cyclotron resonance, and slow wave heating at the fundamental in a single ion species hydrogen plasma, are found to be in good agreement with warm plasma theory at rf power levels less than or equal to 130 kW. Ion heating is negligible off an eigenmode. Ion body temperatures are more than doubled to 75 eV from the 35 eV ohmically heated case with tails comprising 8% of the plasma at 320 eV. No deleterious effects except a non-disruptive 10% shortening of the discharge length caused by impurity influx are noted. A passive mode tracking technique allows approx. = 40% increase in power deposition in a passing eigenmode over that of a fixed frequency rf source. Ion temperatures are limited by charge exchange due to the
Book Synopsis Fast-wave Heating of the W VII A Plasma Near the Second Harmonic of the Ion Cyclotron Frequency by : G. Cattanei
Download or read book Fast-wave Heating of the W VII A Plasma Near the Second Harmonic of the Ion Cyclotron Frequency written by G. Cattanei and published by . This book was released on 1978 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis New Mode Conversion Process and Overdense Plasma Heating in the Electron Cyclotron Range of Frequencies by : S. Nakajima
Download or read book New Mode Conversion Process and Overdense Plasma Heating in the Electron Cyclotron Range of Frequencies written by S. Nakajima and published by . This book was released on 1987 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Ion Heating in the Ion Cyclotron Range of Frequencies in the Wisconsin Tokapole II. by :
Download or read book Ion Heating in the Ion Cyclotron Range of Frequencies in the Wisconsin Tokapole II. written by and published by . This book was released on 1980 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ion temperatures of 75 eV, a doubling of the ohmic heating temperature in a normal discharge, have been achieved using the fast magnetosonic wave heating at the second, third, and fourth harmonics of the cyclotron frequency in a single component hydrogen plasma. The wave launching structure is a single turn, shielded, insulated loop which constitutes the inductor of the rf source tank circuit. Power levels of 800 kW have been applied to the plasma for periods of up to 1.1 milliseconds. Good agreement has been found between theory and experiment for loading and wave propagation in the plasma for m = 0 and m = +1 modes. Eigenmodes have been observed by peaking of both the rf wave amplitude and the loading of the oscillator, as well as by oscillator frequency shifts imposed by their passage.
