Author: Darren Thomas Garnier
Publisher:
ISBN:
Category :
Languages : en
Pages : 132
Book Description
Lithium Pellet Injection Experiments on the Alcator C-Mod Tokamak
Author: Darren Thomas Garnier
Publisher:
ISBN:
Category :
Languages : en
Pages : 132
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 132
Book Description
Lithium Pellet Injection Experiments on the Alcator C-Mod Tokamak
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 131
Book Description
A pellet enhanced performance mode, showing significantly reduced core transport, is regularly obtained after the injection of deeply penetrating lithium pellets into Alcator C-Mod discharges. These transient modes, which typically persist about two energy confinement times, are characterized by a steep pressure gradient (l{sub p} (less-than or equal to) a/5) in the inner third of the plasma, indicating the presence of an internal transport barrier. Inside this barrier, particle and energy diffusivities are greatly reduced, with ion thermal diffusivity dropping to near neoclassical values. Meanwhile, the global energy confinement time shows a 30% improvement over ITER89-P L-mode scaling. The addition of ICRF auxiliary heating shortly after the pellet injection leads to high fusion reactivity with neutron rates enhanced by an order of magnitude over L-mode discharges with similar input powers. A diagnostic system for measuring equilibrium current density profiles of tokamak plasmas, employing high speed lithium pellets, is also presented. Because ions are confined to move along field lines, imaging the Li emission from the toroidally extended pellet ablation cloud gives the direction of the magnetic field. To convert from temporal to radial measurements, the 3-D trajectory of the pellet is determined using a stereoscopic tracking system. These measurements, along with external magnetic measurements, are used to solve the Grad-Shafranov equation for the magnetic equilibrium of the plasma. This diagnostic is used to determine the current density profile of PEP modes by injection of a second pellet during the period of good confinement. This measurement indicates that a region of reversed magnetic shear exists at the plasma core. This current density profile is consistent with TRANSP calculations for the bootstrap current created by the pressure gradient. MHD stability analysis indicates that these plasmas are near the n = (infinity) and the n = 1 marginal stability limits.
Publisher:
ISBN:
Category :
Languages : en
Pages : 131
Book Description
A pellet enhanced performance mode, showing significantly reduced core transport, is regularly obtained after the injection of deeply penetrating lithium pellets into Alcator C-Mod discharges. These transient modes, which typically persist about two energy confinement times, are characterized by a steep pressure gradient (l{sub p} (less-than or equal to) a/5) in the inner third of the plasma, indicating the presence of an internal transport barrier. Inside this barrier, particle and energy diffusivities are greatly reduced, with ion thermal diffusivity dropping to near neoclassical values. Meanwhile, the global energy confinement time shows a 30% improvement over ITER89-P L-mode scaling. The addition of ICRF auxiliary heating shortly after the pellet injection leads to high fusion reactivity with neutron rates enhanced by an order of magnitude over L-mode discharges with similar input powers. A diagnostic system for measuring equilibrium current density profiles of tokamak plasmas, employing high speed lithium pellets, is also presented. Because ions are confined to move along field lines, imaging the Li emission from the toroidally extended pellet ablation cloud gives the direction of the magnetic field. To convert from temporal to radial measurements, the 3-D trajectory of the pellet is determined using a stereoscopic tracking system. These measurements, along with external magnetic measurements, are used to solve the Grad-Shafranov equation for the magnetic equilibrium of the plasma. This diagnostic is used to determine the current density profile of PEP modes by injection of a second pellet during the period of good confinement. This measurement indicates that a region of reversed magnetic shear exists at the plasma core. This current density profile is consistent with TRANSP calculations for the bootstrap current created by the pressure gradient. MHD stability analysis indicates that these plasmas are near the n = (infinity) and the n = 1 marginal stability limits.
Impurity Injection Experiments on the Alcator C-Mod Tokamak
Author: Michael Anthony Graf
Publisher:
ISBN:
Category :
Languages : en
Pages : 190
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 190
Book Description
Hydrogen Recycling at Plasma Facing Materials
Author: C.H. Wu
Publisher: Springer Science & Business Media
ISBN: 9401143315
Category : Technology & Engineering
Languages : en
Pages : 351
Book Description
One of the most important issues in the construction of future magnetic confinement fusion machines is that of the materials of which they are constructed, and one of the key points of proper material choice is the recycle of hydrogen isotopes with materials at the plasma face. Tritium machines demand high safety and economy, which in turn requires the lowest possible T inventory and smallest possible permeation through the plasma facing materials. The recycle behaviour of the in-vessel components must also be known if the plasma reaction is to predictable and controllable, and finally, the fuel cycle and plasma operating regimes may be actively controlled by special materials and methods. The book discusses both laboratory experiments exploring the basic properties of non-equilibrium hydrogen-solid systems (diffusion, absorption, boundary processes) and experimental results obtained from existing fusion machines under conditions simulating future situations to some extent. Contributions are from experts in the fields of nuclear fusion, materials science, surface science, vacuum science and technology, and solid state physics.
Publisher: Springer Science & Business Media
ISBN: 9401143315
Category : Technology & Engineering
Languages : en
Pages : 351
Book Description
One of the most important issues in the construction of future magnetic confinement fusion machines is that of the materials of which they are constructed, and one of the key points of proper material choice is the recycle of hydrogen isotopes with materials at the plasma face. Tritium machines demand high safety and economy, which in turn requires the lowest possible T inventory and smallest possible permeation through the plasma facing materials. The recycle behaviour of the in-vessel components must also be known if the plasma reaction is to predictable and controllable, and finally, the fuel cycle and plasma operating regimes may be actively controlled by special materials and methods. The book discusses both laboratory experiments exploring the basic properties of non-equilibrium hydrogen-solid systems (diffusion, absorption, boundary processes) and experimental results obtained from existing fusion machines under conditions simulating future situations to some extent. Contributions are from experts in the fields of nuclear fusion, materials science, surface science, vacuum science and technology, and solid state physics.
Impurity Injection Experiments on the Alcator C Tokamak
Pellet Injection Experiments in Tokamaks. Part 1
Injection of a Fuel Pellet on the Alcator C Tokamak
Measurement of the Current Density Profile in the Alcator C Tokamak Using Lithium Pellets
Pellet Injection Experiments on the TFR Tokamak
Author: France. Commissariat à l'énergie atomique. Departement de recherches sur la fusion controlee. Equipe TFR.
Publisher:
ISBN:
Category :
Languages : en
Pages : 45
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 45
Book Description