Download or read book Broadening of the Scrape off layer by a Plasma Convection Induced by Toroidal Asymmetries of the Divertor Plates and the Gas puff written by and published by . This book was released on 1995 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the open field line region of the scrape-off layer (SOL), plasma potential is to a considerable degree determined by the boundary conditions on the divertor plates. By introducing toroidal asymmetries of the surface relief of the divertor plates or of their chemical composition, one can create toroidally asymmetric potential variations over the whole SOL and thereby induce convective plasma motion. This motion should lead to a broadening of the SOL and to reduction of beat load on the divertor plates. Convective motion can be induced also by a toroidally asymmetric gas-puff. In the present paper the authors consider all these techniques and evaluate the possible increase in the cross-field transport.
Download or read book 16th IEEE NPSS Symposium Fusion Engineering written by and published by . This book was released on 1995 with total page 900 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1996 with total page 1000 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Index to IEEE Publications written by Institute of Electrical and Electronics Engineers and published by . This book was released on 1996 with total page 1208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Issues for 1973- cover the entire IEEE technical literature.
Download or read book Plasma Flows in the Alcator C Mod Scrape off Layer written by Noah M. Smick and published by . This book was released on 2009 with total page 234 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont.) Toroidal rotation, Pfirsch-Schlilter and transport-driven contributions are unambiguously identified. Parallel flows are found to dominate the high-field particle fluxes; the total poloidally-directed flow carries one half of the particle flux arriving on the inner divertor. As a result, convection is also found to be an important player in high-field side heat transport. In contrast, E_r x B plus parallel flows yield a mostly-toroidal flow component in the low-field SOL. The magnitude of the transport-driven flow component is found to be quantitatively consistent with radial fluctuation-induced particle fluxes measured on the low-field side, identifying this as the primary driver. In contrast, fluctuation-induced flux measurements on the high-field side midplane are found to be essentially zero, thereby excluding an 'inward pinch' effect as the mechanism that closes the mass-flow loop in this region.
Download or read book Investigation of scrape off layer up down asymmetries in diverted plasmas in TEXT Upgrade written by Xavier Pierre Gilles Bonnin and published by . This book was released on 1998 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Survey of Problems in Divertor and Edge Plasma Theory Classic Reprint written by Divertor and Edge Plasma Theory W Group and published by Forgotten Books. This book was released on 2017-11-23 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from A Survey of Problems in Divertor and Edge Plasma Theory On the bases of expected fusion energy production in a fusion reactor and of the energy and particle confinement in tokamaks as presently observed and understood, it is clear that a major design problem for a tokamak reactor is the development of a technique to accept the huge heat and particle fluxes at the first wall. At the same time there should not be a significant impurity reflux into the device. The introduction of a divertor is considered the best solution to the problem of absorbing the fluxes leaving the tokamak while maintaining a pure plasma. The iter cda has identified the divertor design as one of the most difficult design tasks The divertor design has also been a major issue for bpx-cit and tpx. The studies of demo and tokamak reactors also identify the divertor action as a critical item for successful tokamak operation. Given the importance of the divertor, it is no surprise that some time ago major efforts were established to model the plasma outside the separatrix. Typically these codes, of which many exist worldwide, follow the plasma, heat flows, neutrals and impurities in the region from the separatrix to the divertor plates. The system is often conceptually divided into a scrape-off layer adjacent to the core plasma and the somewhat distinct divertor region. These codes demand information from more or less standard fusion plasma physics, the physics of sheaths, and extensive data on atomic and molecular processes and surface physics. The experimental database on the scrape-off layer and divertor is presently rather limited, but in the near future extensive experimental information to compare against model predictions will become available. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
Download or read book Effect of Magnetic Perturbations on Divertor Scrape off Width written by Allen H. Boozer and published by . This book was released on 1977 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book On the Scrape off Layers in a Currentless Toroidal Plasma written by N. Venkataramani and published by . This book was released on 1985 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of Transport Phenomena in the Scrape off Layer and Divertor written by Brian LaBombard and published by . This book was released on 1996 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Scrape off layer in Alcator C Mod written by James L. Terry and published by . This book was released on 2005 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt: (cont.) Evidence that this turbulent transport may play an important role in the core-plasma density limit is presented. Much lower levels of turbulence and no blobs are observed in the high-field-side scrape-off-layer. For single-null magnetic configurations, plasma in the inboard scrape-off-layer appears to be almost entirely a result of plasma flow along field lines from the low-field side. Strong parallel flows with sensitivity to magnetic topology are found, along with strong evidence for momentum coupling between these scrape-off-layer flows and core toroidal rotation
Download or read book Intermittent Divertor Filaments in the National Spherical Torus Experiment and Their Relation to Midplane Blobs written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: While intermittent filamentary structures, also known as blobs, are routinely seen in the low-field-side scrape-off layer of the National Spherical Torus Experiment (NSTX) (Ono et al 2000 Nucl. Fusion 40 557), fine structured filaments are also seen on the lower divertor target plates of NSTX. These filaments, not associated with edge localized modes, correspond to the interaction of the turbulent blobs seen near the midplane with the divertor plasma facing components. The fluctuation level of the neutral lithium light observed at the divertor, and the skewness and kurtosis of its probability distribution function, is similar to that of midplane blobs seen in D[alpha]; e.g. increasing with increasing radii outside the outer strike point (OSP) (separatrix). In addition, their toroidal and radial movement agrees with the typical movement of midplane blobs. Furthermore, with the appropriate magnetic topology, i.e. mapping between the portion of the target plates being observed into the field of view of the midplane gas puff imaging diagnostic, very good correlation is observed between the blobs and the divertor filaments. The correlation between divertor plate filaments and midplane blobs is lost close to the OSP. This latter observation is consistent with the existence of 'magnetic shear disconnection' due to the lower X-point, as proposed by Cohen and Ryutov (1997 Nucl. Fusion 37 621).
Download or read book Particle Transport in the Scrape off Layer and Its Relationship to Discharge Density Limit in Alcator C Mod written by Brian LaBombard and published by . This book was released on 2001 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: (Cont) Small gradients and larger fluctuation levels with longer correlation times are found outside this region (far SOL). Deff in the near SOL increases strongly with local plasma collisionality normalized to the magnetic connection length. As the discharge density limit is approached, Deff and associated fluctuation levels become large across the entire SOL and cross-field heat convection everywhere exceeds parallel conduction losses, impacting the power balance of the discharge.
Download or read book Bias sustained Shield Plasma written by and published by . This book was released on 1992 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: Divertor biasing may provide a method for density and impurity control by enhancing the shielding efficiency of the scrape-off layer. The idea is to make the scrape-off plasma denser and thicker by heating it with a bias-driven current, and by inducing a radial E x B drift. If the bias is applied to flux surfaces at the outer edge of the usual scrape-off layer, a new layer of plasma can be added which is sustained by the bias-supplied power. A simple theoretical model will be presented which shows that there is a threshold condition which must be satisfied in order for the bias-heated plasma to be self-sustaining. The bias-sustained plasma must also be opaque enough to neutrals in order for it to be fueled by a gas puff, which means that it win serve as a shield to the core plasma against neutral impurities and hydrogen. Experiments performed on DIII-D have demonstrated both a modification of the central nickel impurity concentration and an increase in the ionization of hydrogen within the scrape-off layer due to biasing.
Download or read book The Plasma Boundary of Magnetic Fusion Devices written by P.C Stangeby and published by CRC Press. This book was released on 2000-01-01 with total page 738 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Plasma Boundary of Magnetic Fusion Devices introduces the physics of the plasma boundary region, including plasma-surface interactions, with an emphasis on those occurring in magnetically confined fusion plasmas. The book covers plasma-surface interaction, Debye sheaths, sputtering, scrape-off layers, plasma impurities, recycling and control, 1D and 2D fluid and kinetic modeling of particle transport, plasma properties at the edge, diverter and limiter physics, and control of the plasma boundary. Divided into three parts, the book begins with Part 1, an introduction to the plasma boundary. The derivations are heuristic and worked problems help crystallize physical intuition, which is emphasized throughout. Part 2 provides an introduction to methods of modeling the plasma edge region and for interpreting computer code results. Part 3 presents a collection of essays on currently active research hot topics. With an extensive bibliography and index, this book is an invaluable first port-of-call for researchers interested in plasma-surface interactions.
Download or read book Controlled Fusion and Plasma Physics written by Kenro Miyamoto and published by Taylor & Francis. This book was released on 2006-10-23 with total page 393 pages. Available in PDF, EPUB and Kindle. Book excerpt: Resulting from ongoing, international research into fusion processes, the International Tokamak Experimental Reactor (ITER) is a major step in the quest for a new energy source.The first graduate-level text to cover the details of ITER, Controlled Fusion and Plasma Physics introduces various aspects and issues of recent fusion research activ
Download or read book Stellarator and Heliotron Devices written by Masahiro Wakatani and published by Oxford University Press, USA. This book was released on 1998 with total page 462 pages. Available in PDF, EPUB and Kindle. Book excerpt: This monograph describes plasma physics for magnetic confinement of high temperature plasmas in nonaxisymmetric toroidal magnetic fields or stellarators. The techniques are aimed at controlling nuclear fusion for continuous energy production. While the focus is on the nonaxisymmetric toroidal field, or heliotron, developed at Kyoto University, the physics applies equally to other stellarators and axisymmetric tokamaks. The author covers all aspects of magnetic confinement, formation of magnetic surfaces, magnetohydrodynamic equilibrium and stability, single charged particle confinement, neoclassical transport and plasma heating. He also reviews recent experiments and the prospects for the next generation of devices.
