Progress in Quantifying the Edge Physics of H-Mode Regime in DIII-D. 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 Progress in Quantifying the Edge Physics of H-Mode Regime in DIII-D. PDF full book. Access full book title Progress in Quantifying the Edge Physics of H-Mode Regime in DIII-D. by . Download full books in PDF and EPUB format.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Get Book Here
Book Description
Edge conditions in DIII-D are being quantified in order to provide insight into the physics of the H-mode regime. Electron temperature is not the key parameter that controls the L-H transition. Gradients of edge temperature and pressure are much more promising candidates for such parameters. The quality of H-mode confinement is strongly correlated with the height of the H-mode pedestal for the pressure. The gradient of the pressure appears to be controlled by MHD modes, in particular by kink-ballooning modes with finite mode number n. For a wide variety of discharges, the width of the barrier is well described with a relationship that is proportional to ([beta]{sub p}{sup ped})12. An attractive regime of confinement has been discovered which provides steady-state operation with no ELMs, low impurity content and normal H-mode confinement. A coherent edge MHD-mode evidently provides adequate particle transport to control the plasma density and impurity content while permitting the pressure pedestal to remain almost identical to that observed in ELMing discharges.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Get Book Here
Book Description
Edge conditions in DIII-D are being quantified in order to provide insight into the physics of the H-mode regime. Electron temperature is not the key parameter that controls the L-H transition. Gradients of edge temperature and pressure are much more promising candidates for such parameters. The quality of H-mode confinement is strongly correlated with the height of the H-mode pedestal for the pressure. The gradient of the pressure appears to be controlled by MHD modes, in particular by kink-ballooning modes with finite mode number n. For a wide variety of discharges, the width of the barrier is well described with a relationship that is proportional to ([beta]{sub p}{sup ped})12. An attractive regime of confinement has been discovered which provides steady-state operation with no ELMs, low impurity content and normal H-mode confinement. A coherent edge MHD-mode evidently provides adequate particle transport to control the plasma density and impurity content while permitting the pressure pedestal to remain almost identical to that observed in ELMing discharges.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :
Get Book Here
Book Description
In a new high pedestal regime ("Super H-mode") we predicted and accessed DIII-D. Super H-mode was first achieved on DIII-D using a quiescent H-mode edge, enabling a smooth trajectory through pedestal parameter space. By exploiting Super H-mode, it has been possible to access high pedestal pressures at high normalized densities. And while elimination of Edge localized modes (ELMs) is beneficial for Super H-mode, it may not be a requirement, as recent experiments have maintained high pedestals with ELMs triggered by lithium granule injection. Simulations using TGLF for core transport and the EPED model for the pedestal find that ITER can benefit from the improved performance associated with Super H-mode, with increased values of fusion power and gain possible. In similar studies demonstrate that the Super H-mode pedestal can be advantageous for a steady-state power plant, by providing a path to increasing the bootstrap current while simultaneously reducing the demands on the core physics performance.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 10
Get Book Here
Book Description
Recent experiments on DIII-D have extended the hybrid scenario towards the burning plasma regime by incorporating strong electron heating, low torque injection, and edge localized mode (ELM) suppression. Hybrid performance projecting to Q e"10 on ITER at q95=3.1 has been achieved in plasmas with reduced ion/electron temperature ratio or Mach number. Confinement is decreased relative to previous hybrid results, consistent with measurements of increased turbulence at low and intermediate wavenumbers. For the first time, large type-I ELMs have been completely suppressed in a hybrid plasma at q95=3.6 by applying edge resonant magnetic perturbations (RMPs) with toroidal mode number n=3. Additionally, high performance hybrid and steady-state scenario operation has been demonstrated with reduced frequency of wall conditioning with a>95% graphite plasma-facing wall.
Author:
Publisher:
ISBN:
Category : Electronic journals
Languages : en
Pages : 636
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category : Power resources
Languages : en
Pages : 486
Get Book Here
Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 10
Get Book Here
Book Description
This is a proposal to continue support of the authors cooperative research program on DIII-D, under Department of Energy contract DE-FG03-89ER51116. The proposal describes work carried out recently in support of DIII-D data analysis and modeling, with a focus on divertors, edge physics and transport phenomena linking edge and core physics. Proposed work will continue to focus on edge physics, instabilities, the further development of codes to model the plasma, and data analysis in support of related experimental work.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 8
Get Book Here
Book Description
Studies have been conducted in DIII-D to determine the dependence of the power threshold P{sub lh} for the transition to the H-mode regime and the threshold P{sub hl} for the transition from H-mode to L-mode as functions of external parameters. There is a value of the line-averaged density n{sub e} at which P{sub lh} has a minimum and P{sub lh} tends to increase for lower and higher values of n{sub e}. Experiments conducted to separate the effect of the neutral density n0 from the plasma density n{sub e} give evidence of a strong coupling between n0 and n{sub e}. The separate effect of neutrals on the transition has not been determined. Coordinated experiments with JET made in the ITER shape show that P{sub lh} increases approximately as S{sup 0.5} where S is the plasma surface area. For these discharges, the power threshold in DIII-D was high by normal standards, thus suggesting that effects other than plasma size may have affected the experiment. Studies of H-L transitions have been initiated and hysteresis of order 40% has been observed. Studies have also been done of the dependence of the L-H transition on local edge parameters. Characterization of the edge within a few ms prior to the transition shows that the range of edge temperatures at which the transition has been observed is more restrictive than the range of densities at which it occurs. These results suggest that some temperature function is important for controlling the transition.
Author: United States. Congress. House. Committee on Science, Space, and Technology. Subcommittee on Investigations and Oversight
Publisher:
ISBN:
Category :
Languages : en
Pages : 826
Get Book Here
Book Description
Author: C Wendell Horton, Jr
Publisher: World Scientific
ISBN: 9814678686
Category : Science
Languages : en
Pages : 248
Get Book Here
Book Description
The promise of a vast and clean source of thermal power drove physics research for over fifty years and has finally come to collimation with the international consortium led by the European Union and Japan, with an agreement from seven countries to build a definitive test of fusion power in ITER. It happened because scientists since the Manhattan project have envisioned controlled nuclear fusion in obtaining energy with no carbon dioxide emissions and no toxic nuclear waste products.This large toroidal magnetic confinement ITER machine is described from confinement process to advanced physics of plasma-wall interactions, where pulses erupt from core plasma blistering the machine walls. Emissions from the walls reduce the core temperature which must remain ten times hotter than the 15 million degree core solar temperature to maintain ITER fusion power. The huge temperature gradient from core to wall that drives intense plasma turbulence is described in detail.Also explained are the methods designed to limit the growth of small magnetic islands, the growth of edge localized plasma plumes and the solid state physics limits of the stainless steel walls of the confinement vessel from the burning plasma. Designs of the wall coatings and the special 'exhaust pipe' for spent hot plasma are provided in two chapters. And the issues associated with high-energy neutrons — about 10 times higher than in fission reactions — and how they are managed in ITER, are detailed.
Author: Thomas J. Dolan
Publisher: Springer Science & Business Media
ISBN: 1447155564
Category : Technology & Engineering
Languages : en
Pages : 816
Get Book Here
Book Description
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.
