Measurement of Impurity Ion Densities and Energies in the Divertor and Edge Regions of Alcator C-Mod Tokamak. Final Progress Report, March 1994--January 1995

Measurement of Impurity Ion Densities and Energies in the Divertor and Edge Regions of Alcator C-Mod Tokamak. Final Progress Report, March 1994--January 1995
Author:
Publisher:
Total Pages: 5
Release: 1995
Genre:
ISBN:

The authors are investigating impurity production and transport in the divertor and edge regions of the Alcator C-Mod tokamak through spectroscopic techniques. The emphasis is on the low ionization states found in the edge and divertor regions which are indicative of the physical processes related to impurity generation and particle and energy transport in this region. The authors are using a high-resolution visible/ultraviolet spectrograph capable of measuring the Doppler shifts associated with neutral and ion flows and the Doppler broadening associated with neutral and ion temperatures.

Measurement of Impurity Ion Densities and Energies in the Divertor and Edge Regions of Alcator C-Mod Tokamak. Progress Report, February 1, 1992--July 31, 1992

Measurement of Impurity Ion Densities and Energies in the Divertor and Edge Regions of Alcator C-Mod Tokamak. Progress Report, February 1, 1992--July 31, 1992
Author:
Publisher:
Total Pages: 6
Release: 1992
Genre:
ISBN:

A study to investigate impurity production and transport in the divertor and edge regions of the Alcator C-Mod tokamak through spectroscopic techniques is described. A 0.75-meter Czerny-Turner spectrometer with a 1200-g/mm grating and a 35-meter quartz optic bundle transmission line were tested. A high-resolution 2-meter spectrometer will be ordered. Data acquisition considerations are being addressed. (RWR).

Measurement of Impurity Ion Densities and Energies in the Divertor and Edge Regions of Alcator C-Mod Tokamak. [Lab. for Plasma Research, Univ. of Maryland, College Park].

Measurement of Impurity Ion Densities and Energies in the Divertor and Edge Regions of Alcator C-Mod Tokamak. [Lab. for Plasma Research, Univ. of Maryland, College Park].
Author:
Publisher:
Total Pages: 6
Release: 1992
Genre:
ISBN:

A study to investigate impurity production and transport in the divertor and edge regions of the Alcator C-Mod tokamak through spectroscopic techniques is described. A 0.75-meter Czerny-Turner spectrometer with a 1200-g/mm grating and a 35-meter quartz optic bundle transmission line were tested. A high-resolution 2-meter spectrometer will be ordered. Data acquisition considerations are being addressed. (RWR).

Impurity Asymmetries in the Pedestal Region of the Alcator C-Mod Tokamak

Impurity Asymmetries in the Pedestal Region of the Alcator C-Mod Tokamak
Author: Randy Michael Churchill
Publisher:
Total Pages: 216
Release: 2014
Genre:
ISBN:

In an effort to illuminate the effects of the strong plasma gradients in the pedestal region on impurity transport, research was conducted to measure complete sets of impurity density, poloidal and parallel velocity, and temperature at two separate poloidal locations in the pedestal region of the Alcator C-Mod tokamak. To this end, the diagnostic technique gas puff-CXRS was refined and expanded on, allowing for the first time in a tokamak complete measurements of impurities at the high-field side (HFS). Large in-out B5+ impurity density asymmetries were measured in H-mode plasmas with strong boundary electron density gradients, with a build-up of impurity density at the HFS. Impurity temperatures were also found to be asymmetric in the pedestal region, with larger temperatures at the low-field side (LFS). Such temperature asymmetries suggest a significant asymmetry in electron density near the separatrix. In contrast to these H-mode results, plasmas with low boundary electron density gradients, such as L-mode and I-mode, exhibit constant impurity density on a flux surface, even if strong electron temperature gradients are present. Mechanisms which could drive such poloidal asymmetries are explored. Experiments provide evidence against localized impurity sources and fluctuation-induced transport as primary causes. Particle transport timescales are compared, showing that the radial transport becomes comparable to or faster than the parallel transport in the pedestal region. Additionally, modelling of impurity transport using conventional, one-dimensional neoclassical physics fails to correctly reproduce the measured flux-surface averaged impurity density, suggesting along with the timescale estimates that a more complete two-dimensional treatment of impurity particle transport is required. The measured impurity velocities at the LFS and HFS are compared to the canonical form for particle flow velocity within the flux surface of a tokamak. Within the error bars of the measurement, agreement is found with the canonical form. The implications of exact matches to the canonical form are low radial transport, and the E x B drift dominating the perpendicular impurity flow. Further work is motivated into more precise velocity measurements to determine if the velocities exactly match this canonical form.

Magnetic Fusion Technology

Magnetic Fusion Technology
Author: Thomas J. Dolan
Publisher: Springer Science & Business Media
Total Pages: 816
Release: 2014-02-10
Genre: Technology & Engineering
ISBN: 1447155564

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.

Final Report of the Committee on a Strategic Plan for U.S. Burning Plasma Research

Final Report of the Committee on a Strategic Plan for U.S. Burning Plasma Research
Author: National Academies of Sciences, Engineering, and Medicine
Publisher: National Academies Press
Total Pages: 341
Release: 2019-07-01
Genre: Science
ISBN: 0309487439

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.

Bringing Fusion to the U.S. Grid

Bringing Fusion to the U.S. Grid
Author: National Academies of Sciences Engineering and Medicine
Publisher:
Total Pages:
Release: 2021-11-17
Genre:
ISBN: 9780309685382

Fusion energy offers the prospect of addressing the nation's energy needs and contributing to the transition to a low-carbon emission electrical generation infrastructure. Technology and research results from U.S. investments in the major fusion burning plasma experiment known as ITER, coupled with a strong foundation of research funded by the Department of Energy (DOE), position the United States to begin planning for its first fusion pilot plant. Strong interest from the private sector is an additional motivating factor, as the process of decarbonizing and modernizing the nation's electric infrastructure accelerates and companies seek to lead the way. At the request of DOE, Bringing Fusion to the U.S. Grid builds upon the work of the 2019 report Final Report of the Committee on a Strategic Plan for U.S. Burning Plasma Research to identify the key goals and innovations - independent of confinement concept - that are needed to support the development of a U.S. fusion pilot plant that can serve as a model for producing electricity at the lowest possible capital cost.

Nuclear Fusion

Nuclear Fusion
Author: C.M. Braams
Publisher: CRC Press
Total Pages: 352
Release: 2002-06-20
Genre: Science
ISBN: 9781420033786

Fusion research started over half a century ago. Although the task remains unfinished, the end of the road could be in sight if society makes the right decisions. Nuclear Fusion: Half a Century of Magnetic Confinement Fusion Research is a careful, scholarly account of the course of fusion energy research over the past fifty years. The authors outline the different paths followed by fusion research from initial ignorance to present understanding. They explore why a particular scheme would not work and why it was more profitable to concentrate on the mainstream tokamak development. The book features descriptive sections, in-depth explanations of certain physical and technical issues, scientific terms, and an extensive glossary that explains relevant abbreviations and acronyms.

The Fairy Tale of Nuclear Fusion

The Fairy Tale of Nuclear Fusion
Author: L. J. Reinders
Publisher: Springer Nature
Total Pages: 628
Release: 2021-05-20
Genre: Science
ISBN: 3030643441

This carefully researched book presents facts and arguments showing, beyond a doubt, that nuclear fusion power will not be technically feasible in time to satisfy the world's urgent need for climate-neutral energy. The author describes the 70-year history of nuclear fusion; the vain attempts to construct an energy-generating nuclear fusion power reactor, and shows that even in the most optimistic scenario nuclear fusion, in spite of the claims of its proponents, will not be able to make a sizable contribution to the energy mix in this century, whatever the outcome of ITER. This implies that fusion power will not be a factor in combating climate change, and that the race to save the climate with carbon-free energy will have been won or lost long before the first nuclear fusion power station comes on line. Aimed at the general public as well as those whose decisions directly affect energy policy, this book will be a valuable resource for informing future debates.