Download or read book Fast Wave Current Drive in Neutral Beam Heated Plasmas on DIII D written by and published by . This book was released on 1997 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The physics of non-inductive current drive and current profile control using the fast magnetosonic wave has been demonstrated on the DIII-D tokamak. In non-sawtoothing discharges formed by neutral beam injection (NBI), the radial profile of the fast wave current drive (FWCD) was determined by the response of the loop voltage profile to co, counter, and symmetric antenna phasings, and was found to be in good agreement with theoretical models. The application of counter FWCD increased the magnetic shear reversal of the plasma and delayed the onset of sawteeth, compared to co FWCD. The partial absorption of fast waves by energetic beam ions at high harmonics of the ion cyclotron frequency was also evident from a build up of fast particle pressure near the magnetic axis and a correlated increase in the neutron rate. The anomalous fast particle pressure and neutron rate increased with increasing NBI power and peaked when a harmonic of the deuterium cyclotron frequency passed through the center of the plasma. The experimental FWCD efficiency was highest at 2 T where the interaction between the fast waves and the beam ions was weakest; as the magnetic field strength was lowered, the FWCD efficiency decreased to approximately half of the maximum theoretical value.
Download or read book Current Profile Evolution During Fast Wave Current Drive on the DIII D Tokamak written by and published by . This book was released on 1995 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The effect of co and counter fast wave current drive (FWCD) on the plasma current profile has been measured for neutral beam heated plasmas with reversed magnetic shear on the DIII-D tokamak. Although the response of the loop voltage profile was consistent with the application of co and counter FWCD, little difference was observed between the current profiles for the opposite directions of FWCD. The evolution of the current profile was successfully modeled using the ONETWO transport code. The simulation showed that the small difference between the current profiles for co and counter FWCD was mainly due to an offsetting change in the o@c current proffie. In addition, the time scale for the loop voltage to reach equilibrium (i.e., flatten) was found to be much longer than the FWCD pulse, which limited the ability of the current profile to fully respond to co or counter FWCD.
Download or read book Fast Wave Heating and Current Drive in ELMing H mode Plasmas in DIII D written by and published by . This book was released on 1998 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: The DIII-D Fast Wave Current Drive (FWCD) program has concentrated on studying the basic physics of direct electron heating and current drive in low density L-mode discharges from its inception in 1991 through 1996. The more recent DIII-D FWCD work has been aimed at extension of the operating regimes of the experiments, including higher total power by combining FW with NB and 110 GHz ECH. Generally, these higher power levels result in H-mode confinement, and in a quasi-steady-state condition, Edge Localized Modes (ELMs). Over the past two years, the DIII-D FWCD systems have been modified to improve their capabilities under a wide range of dynamic antenna loading conditions, such as those characteristic of ELMing H-modes. In this paper, the first results of extending the FWCD studies to ELMing H-mode discharges are presented.
Download or read book Wave Heating and Current Drive in Plasmas written by Victor L. Granatstein and published by Routledge. This book was released on 1985 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fast Wave Heating and Current Drive in DIII D Discharges with Negative Central Shear written by and published by . This book was released on 1996 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: The noninductive current driven by fast Alfven waves (FWCD) has been applied to discharges in DIII-D with negative central shear. Driven currents as high as 275 kA have been achieved with up to 3 MW of fast wave power with the efficiency and profile as predicted by theory-based modeling. When counter-current FWCD was applied to discharges with negative central shear, the negative shear was strengthened and prolonged, showing that FWCD can help to control the current profile in advanced tokamak discharges. Under some conditions in negative central shear, the plasma spontaneously makes a transition into a regime of improved performance, with a reduction in both the ion and the electron heat diffusivities. Up to 3 MW of fast wave power has been successfully coupled into H-mode discharges with large edge localized modes through use of an innovative decoupler/hybrid power splitter combination.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation of Enhanced Tokamak Performance on DIII D Using Fast Wave Current Drive written by and published by . This book was released on 1993 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fast magnetosonic wave is now recognized to be a leading candidate for noninductive for the tokamak reactor due to the ability of the wave to penetrate to the hot dense core region. Fast wave current drive (FWCD) experiments on D3D have realized up to 120 kA of rf current drive, with up to 40% of the plasma current driven noninductively. The success of these experiments at 60 MHZ with a 2 MW transmitter source capability has led to a major upgrade of the FWCD system. Two additional transmitters, 30 to 120 NM, with a 2 MW source capability each, will be added together with two new four-strap antennas in early 1994. Another major thrust of the D3-D program is to develop advanced tokamak modes of operation, simultaneously demonstrating improvements in confinement and stability in quasi-steady-state operation. In some of the initial advanced tokamak experiments on D3-D with neutral beam heated (NBI) discharges it has been demonstrated that energy confinement nine can be improved by rapidly elongating the plasma to force the current density profile to be more centrally peaked. However, this high-l[sub i] phase of the discharge with the commensurate improvement in confinement is transient as the current density profile relaxes. By applying FWCD to the core of such a [kappa]-ramped discharge it may be possible to sustain the high internal inductance and elevated confinement. Using computational tools validated on the initial DM-D FWCD experiments we find that such a high-l[sub i] advanced tokamak discharge should be capable of sustainment at the 1 MA level with the upgraded capability of the FWCD system.
Download or read book Energy Research Abstracts written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Tokamaks written by John Wesson and published by Oxford University Press. This book was released on 2011-10-13 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Fusion Technology 1994 written by K. Herschbach and published by Newnes. This book was released on 2012-12-02 with total page 892 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of the Symposium on Fusion Technology (SOFT) conference is to set the stage for the exchange of information on the design, construction, and operation of fusion experiments and the technology which is being developed for the next-step devices and for fusion reactors. These proceedings therefore present an up-to-date and throrough review of the state-of-the art in this dynamic field.
Download or read book Energy and water development appropriations for 1991 written by United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water Development and published by . This book was released on 1990 with total page 1850 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Fusion written by and published by . This book was released on 2006 with total page 1102 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Radio Frequency Power in Plasmas written by Ryan and published by American Institute of Physics. This book was released on 1998-04-15 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: This topical conference addresses the use of radio frequency fields for plasma heating, current drive, and MHD control in plasmas. The launching, propagation, mode conversion, and absorption of radio frequency energy in various frequency ranges (Alfven to electron cyclotron) are treated in relation to heating, confinement, plasma production, plasma properties, and current generation. Topics also include basic rf wave physics, rf plasma sources for material processing, and rf technology issues.
Download or read book Results of DIII D Operation with New Enabling Technologies written by and published by . This book was released on 1997 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: Recent experiments on DIII-D have been carried out to understand and explore optimized tokamak operating modes by exploiting control of the plasma current and pressure profiles using new RF current drive and divertor technology. DIII-D emphasizes plasma shape and divertor experiments using a digital plasma control system and extensive diagnostics to develop improved understanding and control of transport barriers in high performance plasmas. The emphasis of the program is to extend the duration of high performance operating modes beyond the plasma current relaxation time by using ICRF and ECH current drive. Engineering features of the new RF systems being developed for these experiments as well as new divertor results are described. DIII-D employs multi-element ICRF antennas for fast-wave electron heating and on-axis current drive and is beginning 110 GHz ECH experiments with MW-level gyrotrons for off-axis current drive. DIII-D employs active cryogenic divertor neutral particle pumping for plasma density and plasma pressure profile control. A divertor modification is now being implemented on DIII-D to pump higher triangularity plasmas and to better baffle neutral backflow from the recycling divertor region.
Download or read book New Ideas in Tokamak Confinement written by Marshall N. Rosenbluth and published by Springer Science & Business Media. This book was released on 1997-05-08 with total page 514 pages. Available in PDF, EPUB and Kindle. Book excerpt: Market: Scientists and students involved in thermonuclear fusion research. Thermonuclear fusion research using the confinement device tokamak represents one of the most prominent science projects in the second half of the 20th century. International Tokamak Community is now committing significant effort and funds to experiments with burning plasma, hot and dense enough to produce significant nuclear fusion reactions. The methods used to enhance tokamak performance have a profound and immediate effect on machine design. This book provides an up-to-date account of research in tokamak fusion and puts forward innovative ideas in confinement physics.
Download or read book Energy and Water Development Appropriations for 2008 Dept of Energy FY 2008 budget justifications science nuclear waste disposal defense nuclear waste disposal written by United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water Development and published by . This book was released on 2007 with total page 1716 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Fusion Energy Program written by United States. Congress. House. Committee on Science, Space, and Technology. Subcommittee on Investigations and Oversight and published by . This book was released on 1990 with total page 820 pages. Available in PDF, EPUB and Kindle. Book excerpt:
