The Quiescent H-mode Regime for High Performance Edge Localized Mode-stable Operation in Future Burning Plasmas [The Quiescent H-mode Regime for High Performance ELM-stable Operation in Future Burning Plasmas]. PDF Download
Are you looking for read ebook online? Search for your book and save it on your Kindle device, PC, phones or tablets. Download The Quiescent H-mode Regime for High Performance Edge Localized Mode-stable Operation in Future Burning Plasmas [The Quiescent H-mode Regime for High Performance ELM-stable Operation in Future Burning Plasmas]. PDF full book. Access full book title The Quiescent H-mode Regime for High Performance Edge Localized Mode-stable Operation in Future Burning Plasmas [The Quiescent H-mode Regime for High Performance ELM-stable Operation in Future Burning Plasmas]. by . Download full books in PDF and EPUB format.
![The Quiescent H-mode Regime for High Performance Edge Localized Mode-stable Operation in Future Burning Plasmas [The Quiescent H-mode Regime for High Performance ELM-stable Operation in Future Burning Plasmas]. PDF](https://books.google.com/books/content/images/frontcover/s8AHuAEACAAJ?fife=w150-h200)
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
For the first time, DIII-D experiments have achieved stationary quiescent H-mode (QH-mode) operation for many energy confinement times at simultaneous ITER-relevant values of beta, confinement, and safety factor, in an ITER similar shape. QH-mode provides excellent energy confinement, even at very low plasma rotation, while operating without edge localized modes (ELMs) and with strong impurity transport via the benign edge harmonic oscillation (EHO). By tailoring the plasma shape to improve the edge stability, the QH-mode operating space has also been extended to densities exceeding 80% of the Greenwald limit, overcoming the long-standing low-density limit of QH-mode operation. In the theory, the density range over which the plasma encounters the kink-peeling boundary widens as the plasma cross-section shaping is increased, thus increasing the QH-mode density threshold. Here, the DIII-D results are in excellent agreement with these predictions, and nonlinear MHD analysis of reconstructed QH-mode equilibria shows unstable low n kink-peeling modes growing to a saturated level, consistent with the theoretical picture of the EHO. Furthermore, high density operation in the QH-mode regime has opened a path to a new, previously predicted region of parameter space, named "Super H-mode" because it is characterized by very high pedestals that can be more than a factor of two above the peeling-ballooning stability limit for similar ELMing H-mode discharges at the same density.
![The Quiescent H-mode Regime for High Performance Edge Localized Mode-stable Operation in Future Burning Plasmas [The Quiescent H-mode Regime for High Performance ELM-stable Operation in Future Burning Plasmas]. PDF](https://books.google.com/books/content/images/frontcover/s8AHuAEACAAJ?fife=w80-h100)
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
For the first time, DIII-D experiments have achieved stationary quiescent H-mode (QH-mode) operation for many energy confinement times at simultaneous ITER-relevant values of beta, confinement, and safety factor, in an ITER similar shape. QH-mode provides excellent energy confinement, even at very low plasma rotation, while operating without edge localized modes (ELMs) and with strong impurity transport via the benign edge harmonic oscillation (EHO). By tailoring the plasma shape to improve the edge stability, the QH-mode operating space has also been extended to densities exceeding 80% of the Greenwald limit, overcoming the long-standing low-density limit of QH-mode operation. In the theory, the density range over which the plasma encounters the kink-peeling boundary widens as the plasma cross-section shaping is increased, thus increasing the QH-mode density threshold. Here, the DIII-D results are in excellent agreement with these predictions, and nonlinear MHD analysis of reconstructed QH-mode equilibria shows unstable low n kink-peeling modes growing to a saturated level, consistent with the theoretical picture of the EHO. Furthermore, high density operation in the QH-mode regime has opened a path to a new, previously predicted region of parameter space, named "Super H-mode" because it is characterized by very high pedestals that can be more than a factor of two above the peeling-ballooning stability limit for similar ELMing H-mode discharges at the same density.
Author: National Academies of Sciences, Engineering, and Medicine
Publisher: National Academies Press
ISBN: 0309487463
Category : Science
Languages : en
Pages : 341
Get Book Here
Book Description
Fusion offers the prospect of virtually unlimited energy. The United States and many nations around the world have made enormous progress toward achieving fusion energy. With ITER scheduled to go online within a decade and demonstrate controlled fusion ten years later, now is the right time for the United States to develop plans to benefit from its investment in burning plasma research and take steps to develop fusion electricity for the nation's future energy needs. At the request of the Department of Energy, the National Academies of Sciences, Engineering, and Medicine organized a committee to develop a strategic plan for U.S. fusion research. The final report's two main recommendations are: (1) The United States should remain an ITER partner as the most cost-effective way to gain experience with a burning plasma at the scale of a power plant. (2) The United States should start a national program of accompanying research and technology leading to the construction of a compact pilot plant that produces electricity from fusion at the lowest possible capital cost.
Author: National Academies of Sciences, Engineering, and Medicine
Publisher: National Academies Press
ISBN: 0309469333
Category : Science
Languages : en
Pages : 61
Get Book Here
Book Description
In January 2003, President George W. Bush announced that the United States would begin negotiations to join the ITER project and noted that "if successful, ITER would create the first fusion device capable of producing thermal energy comparable to the output of a power plant, making commercially viable fusion power available as soon as 2050." The United States and the other ITER members are now constructing ITER with the aim to demonstrate that magnetically confined plasmas can produce more fusion power than the power needed to sustain the plasma. This is a critical step towards producing and delivering electricity from fusion energy. Since the international establishment of the ITER project, ITER's construction schedule has slipped and ITER's costs have increased significantly, leading to questions about whether the United States should continue its commitment to participate in ITER. This study will advise how to best advance the fusion energy sciences in the United States given developments in the field, the specific international investments in fusion science and technology, and the priorities for the next ten years developed by the community and the Office of Fusion Energy Sciences (FES) that were recently reported to Congress. It will address the scientific justification and needs for strengthening the foundations for realizing fusion energy given a potential choice of U.S. participation or not in the ITER project, and develops future scenarios in either case. This interim report assesses the current status of U.S. fusion research and of the importance of burning plasma research to the development of fusion energy as well as to plasma science and other science and engineering disciplines. The final report will present strategies that incorporate continued progress toward a burning plasma experiment and a focus on innovation.
Author: William Trelease
Publisher:
ISBN:
Category : Piperaceae
Languages : en
Pages : 8
Get Book Here
Book Description
Author: D. M. Thomas
Publisher:
ISBN:
Category :
Languages : en
Pages : 6
Get Book Here
Book Description
In recent DIII-D experiments, we concentrated on extending the operating range and improving the overall performance of quiescent H-mode (QH) plasmas. The QH-mode offers an attractive, high-performance operating mode for burning plasmas due to the absence of pulsed edge-localized-mode-driven losses to the divertor (ELMs). Using counter neutral-beam injection (NBI), we achieve steady plasma conditions with the presence of an edge harmonic oscillation (EHO) replacing the ELMs and providing control of the edge pedestal density. These conditions have been maintained for greater than 4s ({approx}30 energy confinement times, {tau}{sub E}, and 2 current relaxation times, {tau}{sub R} [1]), and often limited only by the duration of auxiliary heating. We discuss results of these recent experiments where we use triangularity ramping to increase the density, neutral beam power ramps to increase the stored energy, injection of rf power at the electron cyclotron (EC) frequency to control density profile peaking in the core, and control of startup conditions to completely eliminate the transient ELMing phase.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 18
Get Book Here
Book Description
A path to a new high performance regime has been discovered in tokamaks that could improve the attractiveness of a fusion reactor. Experiments on DIII-D using a quiescent H-mode edge have navigated a valley of improved edge peeling-ballooning stability that opens up with strong plasma shaping at high density, leading to a doubling of the edge pressure over standard edge localized mode (ELM)ing H-mode at these parameters. The thermal energy confinement time increases both as a result of the increased pedestal height and improvements in the core transport and reduced low-k turbulence. Calculations of the pedestal height and width as a function of density using constraints imposed by peeling-ballooning and kinetic-ballooning theory are in quantitative agreement with the measurements.
Author: Dmitri A. Mossessian
Publisher:
ISBN:
Category :
Languages : en
Pages : 34
Get Book Here
Book Description
For steady state H-mode operation, a relaxation mechanism is required to limit build-up of the edge gradient and impurity content. C-Mod sees two such mechanisms - EDA and grassy ELMs, but not large type I ELMs. In EDA the edge relaxation is provided by an edge localized quasicoherent electromagnetic mode that exists at moderate pedestal temperature T400 eV, high pedestal density and high edge safety factor ...3.5, and does not limit the build up of the edge pressure gradient. The q boundary of the operational space of the mode depends on plasma shape, with the q95 limit moving down with increasing plasma triangularity. At high edge pressure gradients and temperatures the mode is replaced by broadband fluctuations (f
Author:
Publisher:
ISBN:
Category : Nuclear fusion
Languages : en
Pages : 654
Get Book Here
Book Description
Author: Jeffrey P. Freidberg
Publisher: Cambridge University Press
ISBN: 1107006252
Category : Science
Languages : en
Pages : 743
Get Book Here
Book Description
Comprehensive, self-contained, and clearly written, this book describes the macroscopic equilibrium and stability of high temperature plasmas.
Author: Dmitri A. Mossessian
Publisher:
ISBN:
Category :
Languages : en
Pages : 32
Get Book Here
Book Description
Under most operational conditions of Alcator C-Mod the dominant type of H-mode is the steady state enhanced Da mode (EDA), characterized by good energy confinement, continuously degraded impurity confinement and absence of regular ELMs. In this regime a quasicoherent (QC) electromagnetic mode ... is observed, localized in the region of the density pedestal. Experimental evidence suggests that the mode is responsible for enhancement of particle transport. It is shown experimentally that the QC mode can exist in a well defined region in edge temperature-safety factor space, favoring high edge q values ... and requiring moderate pedestal temperatureTeped ... As edge temperature and pressure gradient increase, the quasicoherent mode is replaced by broadband low frequency fluctuations (f
