Author: Publisher:
ISBN:
Category : Cyclotron resonance
Languages : en
Pages : 16
Book Description
Fast Wave Current Drive in the Ion Cyclotron Range of Frequencies
Author: Development of Fast-wave ICRF (ion Cyclotron Range of Frequencies) Current Drive Systems at ORNL.
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 5
Book Description
A series of proof-of-principle fast-wave current drive (FWCD) experiments in the ion cyclotron range of frequencies (ICRF) will begin soon on the DIII-D tokamak at General Atomics. These experiments will use a four-strap, 2-MW phased antenna array designed and built at Oak Ridge National Laboratory (ORNL). The antenna array will operate at a frequency of 60 MHz and is expected to drive currents at 0.25 to 0.5 MA in moderate-density ({bar n}{sub e} (approximately) 1.3 x 1019 m−3) plasmas with T{sub e0} (approximately) 4 keV and a toroidal field B = 1 T. We discuss development work undertaken at ORNL to predict the performance of the phased array and its feed circuit and to assist in the design of future FWCD systems. 6 refs., 5 figs.
Fast Wave Current Drive
Author: David A. EhstFast Wave Current Drive in the Ion Cyclotron Range Offrequencies
Author: V. P. BhatnagarFast Wave Current Drive
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The fast wave is one of the two possible wave polarizations which propagate according to the basic theory of cold plasmas. It is distinguished from the other (slow wave) branch by having an electric field vector which is mainly orthogonal to the confining magnetic field of the plasma. The plasma and fast wave qualitatively assume different behavior depending on the frequency range of the launched wave. The high frequency fast wave (HFFW), with a frequency (.omega. 2.pi.)approximately) GHz) much higher than the ion cyclotron frequency (.cap omega./sub i/), suffers electron Landau damping and drives current by supplying parallel momentum to superthermal electrons in a fashion similar to lower hybrid (slow wave) current drive. In the simple theory the HFFW should be superior to the slow wave and can propagate to very high density and temperature without impediment. Experiments, however, have not conclusively shown that HFFW current drive can be achieved at densities above the slow wave current drive limit, possibly due to conversion of the launched fast waves into slow waves by density fluctuations. Alternatively, the low frequency fast wave (LFFW), with frequencies ()approxreverse arrowlt) 100 MHz) only a few times the ion cyclotron frequency, is damped by electron Landau damping and, in a hot plasma ()approxreverse arrowgt) 10 keV), by electron transit time magnetic pumping; current drive is achieved by pushing superthermal electrons, and efficiency is prediocted to be slightly better than for lower hybrid current drive. Most significantly, the slow wave does not propagate in high density plasma when .omega.)approximately) .cap omega./sub i/, so parasitic coupling to the slow wave can be avoided, and no density and temperture limitations are foreseen. Experiments with fast wve current drive invariably find current drive efficiency as good as obtained in lower hybrid experiments at comparable, low temperatures. 45 refs., 4 figs., 1 tab.
Effects of Ion Cyclotron Harmonic Damping on Current Drive in the Lower Hybrid Frequency Range
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
We investigate the ion cyclotron harmonic damping effects on slow and fast waves in the lower hybrid frequency range for tokamak reactor parameters. Inclusion of the higher order terms in the hot plasma dielectric tensor introduces ion cyclotron harmonic damping; these terms also contribute to the real part of the dispersion relation and affect the wave trajectories. However, wave absorption by 15 keV deuterium and tritium ions can be avoided by choosing the slow wave frequency above the lower hybrid frequency and the fast wave frequency below the lower hybrid frequency. But preliminary estimates show that energetic alpha particles tend to absorb both the slow and the fast waves. This absorption may become a serious obstacle for fusion-reactor current drive in the lower hybrid frequency range.
A Theory of Fast Wave Absorption, Transmission and Reflection in the Ion Cyclotron Range of Frequencies
Author: Ion Heating in the Ion Cyclotron Range of Frequencies in the Wisconsin Tokapole II
Author: Alan Pardy BiddlePublisher:
ISBN:
Category : Plasma (Ionized gases)
Languages : en
Pages : 396
Book Description
Radiofrequency Heating of Plasmas,
Author: R. A. CairnsPublisher: CRC Press
ISBN:
Category : Art
Languages : en
Pages : 180
Book Description
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.
Tokamaks
Author: John WessonPublisher: Oxford University Press
ISBN: 0199592233
Category : Science
Languages : en
Pages : 828
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.