Influence of Carbon Impurity on Net Erosion of Reduced-Activation Ferritic/Martensitic Steel and Tungsten Materials Exposed to Hydrogen and Carbon Mixed Ion Beam Relevant to Fusion Plasma Boundary

2006 ◽  
Vol 45 (1A) ◽  
pp. 221-227 ◽  
Author(s):  
Retsuo Kawakami ◽  
Tomohisa Shimada ◽  
Yoshio Ueda ◽  
Masahiro Nishikawa
Keyword(s):  
Martensitic Steel ◽  
Ion Beam ◽  
Plasma Boundary ◽  
Fusion Plasma ◽  
Carbon Impurity ◽  
And Tungsten

Ion beam analysis of deuterium-implanted Al2O3 and tungsten

1998 ◽  
Vol 258-263 ◽  
pp. 1109-1113 ◽  
Author(s):  
R.G Macaulay-Newcombe ◽  
D.A Thompson
Keyword(s):  
Ion Beam ◽  
Ion Beam Analysis ◽  
Beam Analysis ◽  
And Tungsten

Heavy ion beam injection systems for fusion plasma diagnostics

2004 ◽  
Vol 75 (5) ◽  
pp. 1835-1837 ◽  
Author(s):  
I. S. Bondarenko ◽  
A. A. Chmyga ◽  
N. B. Dreval ◽  
S. M. Khrebtov ◽  
A. D. Komarov ◽  
...  
Keyword(s):  
Plasma Diagnostics ◽  
Ion Beam ◽  
Heavy Ion ◽  
Fusion Plasma ◽  
Beam Injection ◽  
Heavy Ion Beam

scholarly journals Response of fusion plasma-facing materials to nanosecond pulses of extreme ultraviolet radiation

2018 ◽  
Vol 36 (3) ◽  
pp. 293-307 ◽  
Author(s):  
Jaroslav Straus ◽  
Karel Kolacek ◽  
Jiri Schmidt ◽  
Oleksandr Frolov ◽  
Monika Vilemova ◽  
...  
Keyword(s):  
Structural Changes ◽  
Focused Ion Beam ◽  
Extreme Ultraviolet ◽  
Laser Energy ◽  
Ion Beam ◽  
Fusion Plasma ◽  
Nanosecond Pulses ◽  
Circular Holes ◽  
Crater Morphology ◽  
Extreme Ultraviolet Radiation

AbstractThe experimental study of damage to tungsten (W), molybdenum (Mo), and silicon carbide (SiC) surfaces induced by focused extreme ultraviolet laser radiation (λ ~ 47 nm/~1.5 ns/21–40 µJ) is presented. It was found that W and Mo behaved similarly: during the first shot, the damaged area is covered by melted and re-solidified material, in which circular holes appear – residua of just opened pores/bubbles, from which pressurized gas/vapors escaped. Next cracks and ruptures appear and the W has a tendency to delaminate its surface layer. Contrary, single-crystalline SiC has negligible porosity and sublimates; therefore, no escape of “pressurized” gas and no accompanying effects take place. Moreover, SiC at sublimating temperature decomposes to elements; therefore, the smooth crater morphology can be related to local laser energy density above ablation threshold. When more shots are accumulated, in all three investigated materials, the crater depth increases non-linearly with number of these shots. The surface morphology was investigated by an atomic force microscope, the surface structure was imaged by a scanning electron microscope (SEM), and the structure below the surface was visualized by SEM directed into a trench that is milled by focused ion beam. Additionally, structural changes in SiC were revealed by Raman spectroscopy.

Simulation of Dynamic Characteristics of Beryllium, Carbon, and Tungsten Dust in the Edge Fusion Plasma

2019 ◽  
Vol 47 (7) ◽  
pp. 3041-3043 ◽  
Author(s):  
N. Kh. Bastykova ◽  
S. K. Kodanova ◽  
T. S. Ramazanov ◽  
A. K. Issanova ◽  
S. A. Maiorov
Keyword(s):  
Dynamic Characteristics ◽  
Fusion Plasma ◽  
And Tungsten

Ion phase-space vortices in 2.5-dimensional simulations

2001 ◽  
Vol 65 (2) ◽  
pp. 107-129 ◽  
Author(s):  
STEINAR BØRVE ◽  
HANS L. PÉCSELI ◽  
JAN TRULSEN
Keyword(s):  
Magnetic Field ◽  
Phase Space ◽  
Ion Beam ◽  
Plasma Boundary ◽  
Space Structures ◽  
Beam Diameter ◽  
Particle In Cell ◽  
Spatial Dimensions ◽  
Cell Simulation ◽  
Transverse Modulation

The formation and propagation of ion phase-space vortices are observed in a numerical particle-in-cell simulation in two spatial dimensions and with three velocity components. The code allows for an externally applied magnetic field. The electrons are assumed to be isothermally Boltzmann-distributed at all times, implying that Poisson's equation becomes nonlinear for the present problem. Ion phase-space vortices are formed by the nonlinear saturation of the ion-ion two-stream instability, excited by injecting an ion beam at the plasma boundary. We consider the effect of a finite beam diameter and a magnetic field, in particular. A vortex instability is observed, appearing as a transverse modulation, which slowly increases with time and ultimately breaks up the vortex. When many vortices are present at the same time, we find that it is their interaction that eventually leads to a gradual filling-up of the phase-space structures. The ion phase-space vortices have a finite lifetime, which is noticeably shorter than that found in one-dimensional simulations. An externally imposed magnetic field can increase this lifetime considerably. For high injected beam velocities in magnetized plasmas, we observe the excitation of electrostatic ion-cyclotron instabilities, but see no associated formation of ion phase-space vortices. The results are relevant, for instance, for the interpretation of observations by instrumented spacecraft in the Earth's ionosphere and magnetosphere.

Quantitative modelling of JET plasmas by computational methods

1987 ◽  
Vol 322 (1563) ◽  
pp. 133-145
Keyword(s):  
Computational Methods ◽  
Linear Equations ◽  
Computing Time ◽  
Initial Boundary ◽  
Plasma Boundary ◽  
Two Dimensions ◽  
Velocity Space ◽  
Tokamak Plasma ◽  
Fusion Plasma ◽  
Magnetic Surfaces

For quantitative predictions the tokamak plasma has to be modelled as a consistent entity. Distinguishing features of fusion plasma theory are the simultaneous importance of a large number of effects, essential multidimensionality in geometrical and velocity space, and a high degree of nonlinearity in the interaction between these effects. Only computational methods, mainly based on linearization, iteration and on procedures for solving huge systems of linear equations, are widely applicable, and provide quantitative ‘point results’ of the ‘numerical experiment’ type. The practical limitations of computer capacity and cost of computing time impose severe limits on details which can be taken into account in computational plasma models. For plasmas of tokamaks such as JET, the models are set up as initial boundary value problems on several time scales, and composed of a cluster of interdependent computer codes. The basic magnetic field-plasma configuration is determined from a one-fluid (magnetohydrodynamic) theory in two dimensions. The macroscopic stability of these configurations is checked. For stable plasmas the secular evolution of a sequence of equilibria is computed by ‘transport codes’. In these the balance equations for the conservation quantities (mass, momentum, energy) are solved for fluxes between, and sources and sinks on, the magnetic surfaces (as determined from equilibrium). These are multifluid equations in one spatial dimension for all charged plasma species including impurities. Important source terms such as electromnetic wave heating, injected particles, and fusion x-particles must be calculated kinetically with at least one additional velocity-space coordinate. At least at the plasma boundary, neutral atoms cannot be neglected. Their distribution is calculated by Monte-Carlo methods in three spatial dimensions (and velocity space). The bulk plasma is usually surrounded by magnetic surfaces or field lines that cross solid walls. Here also, for the transport of charged particles, propagation in two dimensions must be calculated. The consistent combination of these major elements is considered.

Recent progress of high-power negative ion beam development for fusion plasma heating

1997 ◽  
Vol 49 (6) ◽  
pp. 631-639 ◽  
Author(s):  
Kazuhiro Watanabe ◽  
Noboru Akino ◽  
Tetsuo Aoyagi ◽  
Noboru Ebisawa ◽  
Yukio Fujiwara ◽  
...  
Keyword(s):  
High Power ◽  
Recent Progress ◽  
Ion Beam ◽  
Plasma Heating ◽  
Negative Ion ◽  
Fusion Plasma
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