Combination of ion beam techniques, AES and SIMS for the analysis of samples exposed in the plasma boundary of the JET tokamak

1989 ◽  
Vol 14 (9) ◽  
pp. 543-551 ◽  
Author(s):  
J. P. Coad ◽  
J. C. B. Simpson ◽  
G. F. Neill
Keyword(s):  
Ion Beam ◽  
Plasma Boundary

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.

Energetic (∼ 100-keV) tailward-directed ion beam outside the Jovian plasma boundary

1980 ◽  
Vol 7 (1) ◽  
pp. 13-16 ◽  
Author(s):  
S. M. Krimigis ◽  
T. P. Armstrong ◽  
W. I. Axford ◽  
C. O. Bostrom ◽  
C. Y. Fan ◽  
...  
Keyword(s):  
Ion Beam ◽  
Plasma Boundary

scholarly journals Phase space vortices in collisionless plasmas

2003 ◽  
Vol 10 (1/2) ◽  
pp. 75-86 ◽  
Author(s):  
P. Guio ◽  
S. Børve ◽  
L. K. S. Daldorff ◽  
J. P. Lynov ◽  
P. Michelsen ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Space ◽  
Numerical Simulations ◽  
Ion Beam ◽  
Plasma Boundary ◽  
Ion Distribution ◽  
Ion Heating ◽  
Applied Pulse ◽  
Collisionless Plasmas ◽  
Spatial Dimensions

Abstract. Results on the formation and propagation of electron phase space vortices from laboratory experiments are summarized. The electron phase space vortices were excited in a strongly magnetized Q-machine plasma by applying a pulse to a segment of a waveguide surrounding the plasma. Depending on the temporal variation of the applied pulse, one or more phase space vortices can be excited, and their interaction can be followed in space and time. We were able to demonstrate, for instance, an irreversible coalescence of two such vortices. These results are extended by numerical simulations, showing how electron phase space vortices can also be formed by beam instabilities. Furthermore, a study of ion phase space vortices is performed by numerical simulations. Both codes allow for an externally applied magnetic field in three spatial dimensions. 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. By following the evolution of the ion distribution of the velocity perpendicular to the direction of propagation of the injected ion beam, we find a significant ion heating in the direction perpendicular to the magnetic field associated with the ion phase space vortices being formed. The results are relevant, for instance, for the interpretation of observations by instrumented spacecraft in the Earth's ionosphere and magnetosphere.

scholarly journals Gas-discharge plasma application for ion-beam treatment of the holes’ inner surfaces

2021 ◽  
Vol 2064 (1) ◽  
pp. 012079
Author(s):  
D O Sivin ◽  
O S Korneva ◽  
A I Ivanova ◽  
D O Vakhrushev
Keyword(s):  
Stainless Steel ◽  
Ion Beam ◽  
Plasma Boundary ◽  
Axially Symmetric ◽  
Inner Surface ◽  
Ion Beam Treatment ◽  
Steel Aisi ◽  
Aisi 321 ◽  
Nitride Layers ◽  
Stainless Steel Aisi

Abstract The possibility to modify the holes and pipes’ inner surface with focused high-intensity low-energy ion beams was first shown in this work. The studies were carried out using an axially symmetric single-grid system for the ions’ extraction from a free plasma boundary with subsequent ballistic focusing of the ion beam. Ion implantation of the inner surface was carried out in the region of the ion beam defocusing. The studies considered the effect of a nitrogen ions’ beam with energy of 1.4 keV on the inner surface of a tube with a diameter of 20 mm made of stainless steel AISI 321. The beams were formed with a repetition rate of 40 kHz and pulse durations of 5, 7.5 and 10 μs. It is shown that the mutual deposition of the sputtered material on the tube’ opposite sides partly compensates for ion sputtering. As a result of implantation of the inner surface of a pipe made of stainless steel AISI 321, the nitride layers with a thickness of more than 15 microns with a nitrogen dopant content of 22-30 at.% were obtained.

Peculiar Modulation of Ion-Beam Pulses Observed at the Plasma Boundary

1994 ◽  
Vol 63 (4) ◽  
pp. 1624-1625
Author(s):  
Tadao Honzawa ◽  
Toshimitsu Sekizawa ◽  
Yoshifumi Saitou
Keyword(s):  
Ion Beam ◽  
Plasma Boundary
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