Observation and Modeling of Ion Cyclotron Range of Frequencies Waves in the Mode Conversion Region of Alcator C-Mod

Observation and Modeling of Ion Cyclotron Range of Frequencies Waves in the Mode Conversion Region of Alcator C-Mod PDF Author: Yijun Lin
Publisher:
ISBN:
Category :
Languages : en
Pages : 58

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Book Description
The fast magnetosonic wave (FW), mode converted ion cyclotron wave (MC ICW) and ion Bernstein wave (MC IBW) have all been observed and unambiguously identified in the mode conversion region of Alcator C-Mod. The influences of the species mix, mode conversion location and Bpol=Btot have been studied in D(3He) plasmas at B0 ~ 5:4 T (fRF = 50 MHz) and B0 ~ 8 T (fRF = 78 MHz). The RF waves were measured by a phase contrast imaging (PCI) system. The experimental observation is compared with the result from a synthetic PCI diagnostic based upon the full wave code TORIC. Good agreement between the observation and modeling has been obtained on the spatial structure of the RF waves. When the mode conversion layer was off axis, both MC ICW and MC IBW were observed. In 5.4 T near axis mode conversion discharges, double hump spatial structure of the MC waves was observed experimentally and reproduced by the synthetic PCI. Such structure is an indication of the up-down asymmetry of the MC ICW. In 8 T near axis mode conversion discharges, we had the first definitive observation of IBW dominated MC in Alcator C-Mod.

Observation and Modeling of Ion Cyclotron Range of Frequencies Waves in the Mode Conversion Region of Alcator C-Mod

Observation and Modeling of Ion Cyclotron Range of Frequencies Waves in the Mode Conversion Region of Alcator C-Mod PDF Author: Yijun Lin
Publisher:
ISBN:
Category :
Languages : en
Pages : 58

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Book Description
The fast magnetosonic wave (FW), mode converted ion cyclotron wave (MC ICW) and ion Bernstein wave (MC IBW) have all been observed and unambiguously identified in the mode conversion region of Alcator C-Mod. The influences of the species mix, mode conversion location and Bpol=Btot have been studied in D(3He) plasmas at B0 ~ 5:4 T (fRF = 50 MHz) and B0 ~ 8 T (fRF = 78 MHz). The RF waves were measured by a phase contrast imaging (PCI) system. The experimental observation is compared with the result from a synthetic PCI diagnostic based upon the full wave code TORIC. Good agreement between the observation and modeling has been obtained on the spatial structure of the RF waves. When the mode conversion layer was off axis, both MC ICW and MC IBW were observed. In 5.4 T near axis mode conversion discharges, double hump spatial structure of the MC waves was observed experimentally and reproduced by the synthetic PCI. Such structure is an indication of the up-down asymmetry of the MC ICW. In 8 T near axis mode conversion discharges, we had the first definitive observation of IBW dominated MC in Alcator C-Mod.

Low-Frequency Waves in Space Plasmas

Low-Frequency Waves in Space Plasmas PDF Author: Andreas Keiling
Publisher: John Wiley & Sons
ISBN: 1119055024
Category : Science
Languages : en
Pages : 528

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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.

Ultrahigh Resolution Simulations of Mode Converted Ion Cyclotron Waves and Lower Hybrid Waves

Ultrahigh Resolution Simulations of Mode Converted Ion Cyclotron Waves and Lower Hybrid Waves PDF Author: John C. Wright
Publisher:
ISBN:
Category :
Languages : en
Pages : 16

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Book Description
FullWave studies of mode conversion (MC) processes in toroidal plasmas have required prohibitive amount of computer resources in the past because of the disparate spatial scales involved. The TORIC code [1] solves the linear sixth order reduced wave equation for the ion cyclotron range of frequencies (ICRF), in toroidal geometry using a Fourier representation for the poloidal dimension and finite elements in the flux dimension. The range of problems that TORIC can do has been extended through both new serial algorithms and parallelization of memory and processing. The implementation of out-of-core memory management, FFT convolutions, and improved memory management brought MC studies just into range of the serial version of the code running on a NERSC Cray SV1. Some simple tests and arguments show that more resolution than is possible on a single processor system is needed to fully resolve these scenarios. By distributing the large linear system across many processors in conjunction with the out-of-core technique, the resolution limitations are effectively removed. ScaLAPACK is used to do the linear algebra operations and message passing interface (MPI) is used to distribute the significant amount of postprocessing. The new parallel version of the code can easily do the most difficult MC problems on present day tokamaks (Alcator C-Mod and Asdex-Upgrade), with only 32 pc from a local Beowulf cluster. Using 48 or more processors admits us to problems in the lower hybrid range of frequencies. Key words: TORIC ICRF FastWave IBW Bernstein LowerHybrid Simulation FullWave. PACS: 52.25. Mq 52.35.H 52.50. Sw 52.65.-y.

Wave-particle Studies in the Ion Cyclotron and Lower Hybrid Range of Frequencies in Alcator C-Mod

Wave-particle Studies in the Ion Cyclotron and Lower Hybrid Range of Frequencies in Alcator C-Mod PDF Author: Paul Bonoli
Publisher:
ISBN:
Category :
Languages : en
Pages : 202

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Book Description
(cont.) It is shown that this off-axis LH current drive can be used to create discharges with non-monotonic profiles of the current density and reversed shear. An advanced tokamak operating regime near the ideal no-wall [beta]-limit is described for C-Mod, where about 70% of the current is driven through the bootstrap effect. The LH power is coupled to C-Mod through a waveguide launcher consisting of four rows (vertically) with 24 guides per row (toroidally). A detailed description of the LH launcher fabrication is given in this paper along with initial operation results.

Plasma Scattering of Electromagnetic Radiation

Plasma Scattering of Electromagnetic Radiation PDF Author: John Sheffield
Publisher: Academic Press
ISBN: 0080952038
Category : Science
Languages : en
Pages : 512

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Book Description
This work presents one of the most powerful methods of plasma diagnosis in exquisite detail, to guide researchers in the theory and measurement techniques of light scattering in plasmas. Light scattering in plasmas is essential in the research and development of fusion energy, environmental solutions, and electronics. Referred to as the "Bible" by researchers, the work encompasses fusion and industrial applications essential in plasma research. It is the only comprehensive resource specific to the plasma scattering technique. It provides a wide-range of experimental examples and discussion of their principles with worked examples to assist researchers in applying the theory. Computing techniques for solving basic equations helps researchers compare data to the actual experiment New material on advances on the experimental side, such as the application of high density plasmas of inertial fusion Worked out examples of the scattering technique for easier comprehension of theory

Tokamaks

Tokamaks PDF Author: John Wesson
Publisher: Oxford University Press
ISBN: 0199592233
Category : Science
Languages : en
Pages : 828

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Book Description
The tokamak is the principal tool in controlled fusion research. This book acts as an introduction to the subject and a basic reference for theory, definitions, equations, and experimental results. The fourth edition has been completely revised, describing their development of tokamaks to the point of producing significant fusion power.

Dissertation Abstracts International

Dissertation Abstracts International PDF Author:
Publisher:
ISBN:
Category : Dissertations, Academic
Languages : en
Pages : 734

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Energy Research Abstracts

Energy Research Abstracts PDF Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 498

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Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 836

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Chemical Abstracts

Chemical Abstracts PDF Author:
Publisher:
ISBN:
Category : Chemistry
Languages : en
Pages : 2018

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