Download or read book A Fast Visible Camera Divertor Imaging Diagnostic on DIII D written by and published by . This book was released on 2007 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent campaigns, the Photron Ultima SE fast framing camera has proven to be a powerful diagnostic when applied to imaging divertor phenomena on the National Spherical Torus Experiment (NSTX). Active areas of NSTX divertor research addressed with the fast camera include identification of types of EDGE Localized Modes (ELMs)[1], dust migration, impurity behavior and a number of phenomena related to turbulence. To compare such edge and divertor phenomena in low and high aspect ratio plasmas, a multi-institutional collaboration was developed for fast visible imaging on NSTX and DIII-D. More specifically, the collaboration was proposed to compare the NSTX small type V ELM regime [2] and the residual ELMs observed during Type I ELM suppression with external magnetic perturbations on DIII-D[3]. As part of the collaboration effort, the Photron camera was installed recently on DIII-D with a tangential view similar to the view implemented on NSTX, enabling a direct comparison between the two machines. The rapid implementation was facilitated by utilization of the existing optics that coupled the visible spectral output from the divertor vacuum ultraviolet UVTV system, which has a view similar to the view developed for the divertor tangential TV camera [4]. A remote controlled filter wheel was implemented, as was the radiation shield required for the DIII-D installation. The installation and initial operation of the camera are described in this paper, and the first images from the DIII-D divertor are presented.
Download or read book A Tangentially Viewing Visible TV System for the DIII D Divertor written by and published by . This book was released on 1996 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: A video camera system has been installed on the DIII-D tokamak for 2-D spatial studies of line emission in the lower divertor region. The system views the divertor tangentially from an outer port at approximately the height of the X-point. At the tangency plane the entire divertor from inner wall to outside the DIII-D bias ring is viewed with spatial resolution of approximately 1 cm. The image contains information from approximately 90 degrees of toroidal angle. In a recent upgrade, remotely controllable filter changers were added which have produced images from nominally identical shots using a series of spectral lines. Software was developed to calculate the response function matrix using distributed computing techniques and assuming toroidal symmetry. Standard sparse matrix algorithms are then used to invert the 3-D images onto a poloidal plane. Spatial resolution of the inverted images is 2 cm; higher resolution simply increases the size of the response function matrix. Initial results from a series of experiments with multiple identical shots show that the emission from CII and CIII, which appears along the inner scrape-off layer above and below the X-point during ELMing H-mode, moves outward and becomes localized near the X-point in Partially Detached Divertor (PDD) operation.
Download or read book Plasma Diagnostics for the DIII D Divertor Upgrade written by and published by . This book was released on 1990 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: The DIII-D tokamak is being upgraded to allow for divertor biasing, baffling, and pumping experiments. This paper gives an overview of the new diagnostics added to DIII-D as part of this Advanced Divertor Program. They include tile current monitors, fast reciprocating Langmuir probes, a fixed probe array in the divertor, fast neutral pressure gauges, and H{sub {alpha}} measurements with TV cameras and fiber optics coupled to a high resolution spectrometer. 9 refs.
Download or read book Magnetic Fusion Technology written by Thomas J. Dolan and published by Springer Science & Business Media. This book was released on 2014-02-10 with total page 816 pages. Available in PDF, EPUB and Kindle. Book excerpt: Magnetic Fusion Technology describes the technologies that are required for successful development of nuclear fusion power plants using strong magnetic fields. These technologies include: • magnet systems, • plasma heating systems, • control systems, • energy conversion systems, • advanced materials development, • vacuum systems, • cryogenic systems, • plasma diagnostics, • safety systems, and • power plant design studies. Magnetic Fusion Technology will be useful to students and to specialists working in energy research.
Download or read book DIAGNOSIS OF EDGE LOCALIZED MODE EVOLUTION IN DIII D USING FAST GATED CID AND INFRARED CAMERAS written by and published by . This book was released on 2003 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The tangentially viewing visible and vertically viewing infrared cameras systems on DIII-D were upgraded to permit emission measurements during edge localized modes (ELMs) with integration times as short as 1 and 100[micro]s respectively. The visible system was used to obtain 2-D poloidal profiles of CIII (465 nm) and D[sub[alpha]] (656.3 nm) emission with 20[micro]s integration during various stages of ELM events in the lower DIII-D divertor. The infrared (IR) system was used to measure the heat flux to the divertor targets at 10 kHz with 100[micro]s exposure. Upgrades to the data processing and storage systems permitted efficient comparison of the temporal evolution of these measurements.
Download or read book Fusion Energy written by and published by . This book was released on 1997 with total page 962 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Visible Spectroscopy in the DIII D Divertor written by and published by . This book was released on 1996 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spectroscopy measurements in the DIII-D divertor have been carried out with a survey spectrometer which provides simultaneous registration of the visible spectrum over the region 400--900 nm with a resolution of 0.2 nm. Broad spectral coverage is achieved through use of a fiberoptic transformer assembly to map the curved focal plane of a fast (f/3) Rowland-circle spectrograph into a rastered format on the rectangular sensor area of a two-dimensional CCD camera. Vertical grouping of pixels during CCD readout integrates the signal intensity over the height of each spectral segment in the rastered image, minimizing readout time. For the full visible spectrum, readout time is 50 ms. Faster response time (
Download or read book Observation of Dust in DIII D Divertor and SOL by Visible Imaging written by and published by . This book was released on 2007 with total page 3 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dust is commonly found in fusion devices. Though generally of no concern in the present day machines, dust may pose serious safety and operational concerns for ITER. Micron-size dust usually dominates the samples collected from tokamaks. During a plasma discharge micron-size dust particles can become highly mobile and travel over distances of a few meters. Once inside the plasma, dust particles heat up to over 3000 K and emit thermal radiation that can be detected by visible imaging techniques. Observations of naturally occurring and artificially introduced dusts have been performed in DIII-D divertor and scrape-off layer (SOL) using standard frame rate CMOS cameras, a gated-intensified CID camera, and a fast-framing CMOS camera. In the first 2-3 plasma discharges after a vent with personnel entry inside the vacuum vessel ('dirty vent') dust levels were quite high with thousands of particles observed in each discharge. Individual particles moving at velocities of up to a few hundred m/s and breakup of larger particles into pieces were observed. After about 15 discharges dust was virtually gone during the stationary portion of a discharge, and appeared at much reduced levels during the plasma initiation and termination phases. After a few days of plasma operations (about 70 discharges) dust levels were further reduced to just a few observed events per discharge except in discharges with current disruptions that produced significant amounts of dust. An injection of a few milligram of micron-size (6 micron median diameter) carbon dust into a high-power lower single-null ELMing H-mode discharge with strike points swept across the lower divertor floor was performed. A significant increase of the core carbon radiation was observed for about 250 ms after the injection, as the total radiated power increased twofold. Dust particles from the injection were observed by the fast framing camera in the outboard SOL near the midplane. The amount of dust observed by the fast camera immediately after the injection was.
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 Diagnostics for the DIII D Radiative Divertor written by and published by . This book was released on 1995 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper reviews the design of new diagnostics and the modifications to existing diagnostics needed to carry out radiative divertor experiments in DIII-D following installation in late 1996 of a set of baffle structures that will restrict the backflow to the core plasma of neutral deuterium atoms and impurity gases. The divertor slots formed by the new baffle structures will inhibit the easy view of the divertor legs and target plates that the open divertor geometry in DIII-D currently affords. We review a basic set of diagnostics that are needed to demonstrate the reduction of divertor heat loading and radiative dissipation of energy within the divertor. This will include IR cameras, bolometry, foil bolometers, and Langmuir probes. Within the limits of available funding, we will implement a supplemental set of instruments which provide a more detailed understanding of the underlying physical processes. Many existing diagnostics require only re-aiming to provide proper coverage of the initial 23 cm long divertor plasma configuration (X- point to floor distance). Other diagnostics need extensive reconfiguration using in-vessel fiber-optic bundles or high power laser mirrors. The new divertor baffle panels provide a protective shelf for diagnostic hardware mounted underneath them, but the water cooling channels in the panels limit the permissible size of through holes and, thereby, restrict the available views of under-the- baffle diagnostics. The successful resolution of the design and implementation of these diagnostic modifications is dependent on a strong coordination between GA and its many diagnostic collaborators.
Download or read book Fusion Energy 1996 written by International Atomic Energy Agency and published by Fusion Energy 1996. This book was released on 1997 with total page 954 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the Sixteenth International Conference, formerly called the International Conference on Plasma Physics and Controlled Nuclear Fusion Research, Montreal, 7-11 October 1996. The papers presented reflect the excellent progress achieved since the last conference in Seville 1994. Among many other achievements, the Tokamak Fusion Test Reactor has produced over 10 MW of fusion power, the JT-60U experiment has demonstrated plasma conditions equivalent to breakeven, the reversed shear mode has been demonstrated, low aspect ratio tokamaks have produced promising results and plans have been drawn up for powerful new inertial confinement fusion experiments.
Download or read book Fusion Science and Technology written by and published by . This book was released on 2008 with total page 808 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evolution of 2D Visible and VUV Divertor Emission Profiles During DIII D H MODE Detachment Transitions written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The peak heat flux to divertor target surfaces (P[sub div]) must be reduced, compared with present experimental levels, before a tokamak operating in the high confinement regime (H-mode) can be extrapolated to a reactor. Partially Detached Divertor (PDD) operation[1], in which deuterium gas is injected into an H-mode plasma, reduces P[sub div] by factors of 3-5 in DIII-D.A key element in the physics model of PDD operation is that carbon radiation near the X-point dissipates the energy flowing in the scrape-off-layer (SOL) before it enters the divertor[2]. This allows the divertor temperature to be low, density to be high and thereby reduces the heat flux and ion particle flux to the targets both by reduced recycling and increased recombination. Previous line integrated SPRED measurements[3] and computer simulations indicated that the 155 nm[Delta]n= 0 transition of C[sup 3+] was the main power radiator from carbon during PDD operation. This paper presents the first 2D profiles of 155 nm CIV emission in any tokamak divertor. The images were obtained on DIII-D with a new tangentially viewing VUV camera[4] and established image reconstruction techniques[5]. The discharges were lower single null configurations with, I[sub p]= 1.75 MA, B[sub T]= 2.1[Tau], q[sub 95]= 3.2, P[sub inj]= 9 MW, [kappa]= 1.9 and the[nabla]B drift toward the lower divertor. After establishing an ELMing H-mode with neutral beam injection, deuterium gas was injected at 17 Pa m[sup 3]/s (130 T[ell]/s) to increase the divertor density and produce a transition to PDD operation. A practical discharge scenario is given in Ref.[2].
Download or read book Electrical Electronics Abstracts written by and published by . This book was released on 1997 with total page 1860 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reconstruction of Detached Divertor Plasma Conditions in DIII D Using Spectroscopic and Probe Data written by P. Stangeby and published by . This book was released on 2004 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt: For some divertor aspects, such as detached plasmas or the private flux zone, it is not clear that the controlling physics has been fully identified. This is a particular concern when the details of the plasma are likely to be important in modeling the problem--for example, modeling co-deposition in detached inner divertors. An empirical method of ''reconstructing'' the plasma based on direct experimental measurements may be useful in such situations. It is shown that a detached plasma in the outer divertor leg of DIII-D can be reconstructed reasonably well using spectroscopic and probe data as input to a simple onion-skin model and the Monte Carlo hydrogenic code, EIRENE. The calculated 2D distributions of n{sub e} and T{sub e} in the detached divertor were compared with direct measurements from the divertor Thomson scattering system, a diagnostic capability unique to DIII-D.
Download or read book Fusion Energy Update written by and published by . This book was released on 1986 with total page 614 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Engineering Installation Testing and Initial Operation of the DIII D Advanced Divertor written by and published by . This book was released on 1990 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advanced Divertor (AD) for General Atomics tokamak, DIII-D, was installed in the summer of 1990. The AD has enabled two classes of physics experiments to be run: divertor biasing and divertor baffling. Both are new experiments for DIII-D. The AD has two principal components: (1) a continuous ring electrode; and (2) a toroidally symmetric baffle. The tokamak can be run in bias baffle or standard DIII-D divertor modes by accurate positioning of the outer divertor strike point through the use of the DIII-D control system. The paper covers design, analysis, fabrication, installation, instrumentation, testing, initial operation, and future plans for the Advanced Divertor from an engineering viewpoint. 2 refs., 5 figs.
