Download or read book Effects of Plasma Shape and Profiles on Edge Stability in DIII D written by and published by . This book was released on 1998 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of recent experimental and theoretical studies concerning the effects of plasma shape and current and pressure profiles on edge instabilities in DIII-D are presented. Magnetic oscillations with toroidal mode number n H"2--9 and a fast growth time?−1 = 20--150?s are often observed prior to the first giant type 1 ELM in discharges with moderate squareness. High n ideal ballooning second stability access encourages edge instabilities by facilitating the buildup of the edge pressure gradient and bootstrap current density which destabilize the intermediate to low n modes. Analysis suggests that discharges with large edge pressure gradient and bootstrap current density are more unstable to n> 1 modes. Calculations and experimental results show that ELM amplitude and frequency can be varied by controlling access to the second ballooning stability regime at the edge through variation of the squareness of the discharge shape. A new method is proposed to control edge instabilities by reducing access to the second ballooning stability regime at the edge using high order local perturbation of the plasma shape in the outboard bad curvature region.

Download or read book Impact of Edge Current Density and Pressure Gradient on the Stability of DIII D High Performance Discharges written by and published by . This book was released on 1997 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the major goals of advanced tokamak research is to develop plasma configurations with good confinement and improved stability at high [beta]. In DIII-D, various high performance configurations with H- and VH-mode edges have been produced. These include discharges with poloidal cross sections in the forms of dee and crecent shapes, single- and double-null divertors, and with various central magnetic shear profiles and current profile peakedness. All these discharges exhibit confinement in the outer plasma region which leads to a large edge pressure gradient and a large edge bootstrap current driven by this steep pressure gradient. These edge conditions often drive an instability near the edge region which can severely degrade the discharge performance. An understanding of this edge instability is essential to sustain an enhance discharge performance.

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 The Effect of Plasma Shape on H Mode Pedestal Characteristics on DIII D written by and published by . This book was released on 1999 with total page 21 pages. Available in PDF, EPUB and Kindle. Book excerpt: The characteristics of the H-mode are studied in discharges with varying triangularity and squareness. The pressure at the top of the H-mode pedestal increases strongly with triangularity primarily due to an increase in the margin by which the edge pressure gradient exceeds the ideal ballooning mode first stability limit. Two models are considered for how the edge may exceed the ballooning mode limit. In one model [1], access to the ballooning mode second stable regime allows the edge pressure gradient and associated bootstrap current to continue to increase until an edge localized, low toroidal mode number, ideal kink mode is destabilized. In the second model [2], the finite width of the H-mode transport barrier, and diamagnetic effects raise the pressure gradient limit above the ballooning mode limit. We observe a weak inverse dependence of the width of the H-mode transport barrier, [Delta], on triangularity relative to the previously obtained [3] scaling [Delta] ∞ ([beta]{sub P}{sup PED})12. The energy loss for Type I ELMs increases with triangularity in proportion to the pedestal energy increase. The temperature profile is found to respond stiffly to changes in T{sup PED} at low temperature, while at high temperature the response is additive. The response of the density profile is also found to play a role in the response of the total stored energy to changes in the W{sup PED}.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 692 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fusion Nucl aire written by and published by . This book was released on 2006 with total page 730 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Electron Cyclotron Emission And Electron Cyclotron Resonance Heating Ec 16 Proceedings Of The 16th Joint Workshop With Cd rom written by Ronald Prater and published by World Scientific. This book was released on 2011-02-21 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceedings volume, the sixteenth in a biannual series, presents a snapshot of the state of current research worldwide on Electron Cyclotron Emission (ECE) and Electron Cyclotron Resonance Heating (ECRH) and related technologies. The papers address the physics, both theory and experiment, of ECE and ECRH. The technologies of high power millimeter-wave sources — gyrotrons — and transmission lines and launchers are included. The focus is on physics and technology relevant to the research and development of nuclear fusion.

Download or read book Electron Cyclotron Emission and Electron Cyclotron Resonance Heating EC 16 written by Ronald Prater and published by World Scientific. This book was released on 2011 with total page 427 pages. Available in PDF, EPUB and Kindle. Book excerpt: This proceedings volume, the sixteenth in a biannual series, presents a snapshot of the state of current research worldwide on Electron Cyclotron Emission (ECE) and Electron Cyclotron Resonance Heating (ECRH) and related technologies. The papers address the physics, both theory and experiment, of ECE and ECRH. The technologies of high power millimeter-wave sources ? gyrotrons ? and transmission lines and launchers are included. The focus is on physics and technology relevant to the research and development of nuclear fusion.

Download or read book Energy and Water Development Appropriations For 2006 Part 4B 109 1 Hearings written by and published by . This book was released on 2005 with total page 1444 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Energy and water development appropriations for 2005 written by United States. Congress. House. Committee on Appropriations. Subcommittee on Energy and Water Development and published by . This book was released on 2004 with total page 1440 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Department of Energy s Restructured Fusion Energy Sciences Program written by United States. Congress. House. Committee on Science. Subcommittee on Energy and Environment and published by . This book was released on 1996 with total page 682 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Physics Briefs written by and published by . This book was released on 1994 with total page 934 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Government Reports Annual Index written by and published by . This book was released on 1993 with total page 1832 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 ITER Concept Definition written by and published by . This book was released on 1989 with total page 592 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Production and Stability of High beta DIII D Discharges with Reversed Magnetic Shear written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Plasma configurations with reversed magnetic shear have been proposed for steady-state tokamak operation since the plasma profiles can be made consistent with good confinement, high bootstrap current fraction, and stability at very high beta. The stability of reversed magnetic shear discharges with beta up to 11% has previously been demonstrated in DIII-D. Reversed magnetic shear (RMS) refers to a safety factor profile, q([rho]), which is a non-monotonic function of minor radius, [rho]. The magnetic shear S[equivalent-to] ([rho]/q) dq/d[rho] is negative within the plasma core and positive at the edge. When S

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.