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Citations Index
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Articles With Citations
to Z. Abou-Assaleh
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Theoretical Plasma
Physics |
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Controlled Thermonuclear Fusion Energy |
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2009 |
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2009 No 04 |
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https://spiral.imperial.ac.uk/handle/
10044/1/5292
Imperial College
London. Department of Physics.
Item Type: Thesis or dissertation
Investigations of the MAST SOL using the
reciprocating probe system
Sebastian Tallents
Supervised by Michael Coppins
Submitted in part fulfilment of the requirements
for the degree of
Doctor of Philosophy in Physics of Imperial
College London
and the Diploma of Imperial College London
January 2009
Abstract:
Parallel flow in the scrape-off layer is a major
area of interest in tokamak research, impacting on impurity
transport, tritium retention and H-mode access. The work presented
here is the first major investigation of SOL flow in the Mega
Ampere Spherical Tokamak (MAST), using a Gundestrup probe
specifically designed for the task. The results of a parameter
scan in poloidal field, Bѳ, and temperature, T, of parallel
velocity at the outboard mid-plane are presented, and the results
and scalings compared to B2SOLPS5.0 simulations of MAST and a
simple analytical model, in order to identify the relative
importance of drift mechanisms (such as Pfirsch-Schluter and E ×
B) for driving parallel flow. The results show the predicted
linear scaling with temperature and poloidal field strength, but
also suggest a density dependence. Another major are of interest
is the discovery in recent years of coherent filamentary
structures that are radially convected through the L-mode SOL.
These filaments are believed to contain sharp gradients in
temperature, density and plasma potential, complicating probe
analysis. An investigation to characterise the intermittency of
the MAST SOL, it’s dependencies on poloidal field strength,
density or temperature, and the impact of the filaments on probe
measurements was also carried out, and a probe was built to
further investigate the structure and dynamics of the filaments.
Based on these experiments a method for resolving the flow in the
filaments and background plasma was developed and applied in the
flow experiments described above. It is found that the parallel
Mach numbers are lower in the filaments than the ambient plasma in
the far SOL — suggesting either ion temperatures are at least on
the order of 4 times the electron temperature — or parallel flow
velocity is substantially lower in the filaments than in the
background plasma.
Bibliography
...
[94] S. L. Gulick, B. L. Stansfield,
Z. Abou-Assaleh, C. Boucher, J. P. Matte, T. W. Johnston, and
R. Marchand. Measurement of pre-sheath flow
velocities by laser-induced fluorescence. Journal of
Nuclear Materials, 176 &
177:1059–1063, 1990.
...
Investigations of the MAST SOL using the
reciprocating probe system
Sebastian Tallents
Issue Date: Jan-2009
Date Awarded: Aug-2009
URI:
http://hdl.handle.net
/10044/1/5292
Supervisor: Coppins, Michael
Sponsor/Funder: United Kingdom Engineering and
Physical Sciences Research Council and by the European Communities
under the Contract of Association between EURATOM and UKAEA
Author: Tallents, Sebastian
Department: Physics
Publisher: Imperial College London
Qualification Level: Doctoral
Qualification Name: Doctor of Philosophy (PhD)
Appears in Collections:
Physics PhD theses
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2009 No 03 |
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Journal of Physics D: Applied Physics
https://iopscience.iop.org/
article/10.1088/0022-3727/42/22/225205
Effect of ion–neutral collision on the deduction of Mach number
in collisional plasmas
Yong-Sup Choi1, Kyu-Sun Chung2, Hyun-Jong Woo2, Myung-Jae Lee3 and
Taehyeop Lho
Published 27 October 2009 • 2009 IOP Publishing Ltd
Journal of Physics D: Applied Physics, Volume 42, Number 22
Citation Yong-Sup Choi et al 2009 J. Phys. D: Appl. Phys. 42
225205
Abstract
A new unmagnetized collisional Mach probe theory is developed in
order to resolve the collisional effect on Mach probe analysis by
including ionization, charge and momentum transfer of ions in the
perturbation region of a Mach probe. A fluid model is established
by assuming Boltzmann electrons and taking the moments of the
one-dimensional Boltzmann transport equation, which contains the
two-dimensional transport information as a source, after adding a
collisional term. A new relation between the flow velocity and the
ratio of the ion sheath current densities is obtained, and is
compared with those by a collisionless kinetic theory and a
particle-in-cell simulation in the applicable range of these
theories. A new relation between flow velocity and the ratio of
the ion sheath current densities shows that ion–neutral collisions
have a very strong effect to produce much smaller Mach numbers
from the same ratio than those by collisionless models.
https://iopscience.iop.org/article/
10.1088/0022-3727/42/22/225205
https://www.researchgate.net/publication/
230986454_Effect_of_
ion-neutral_collision_on_the_deduction
_of_Mach_number_in_collisional_plasmas
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2009 No 02 |
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Plasma Sources Science and TechnologyPlasma Sources Sci.
Technol. 18 (2009) 025012 (10pp)
doi:10.1088/0963-0252/18/2/025012
https://iopscience.iop.org/article/10.1088/0963-0252/18/2/025012/meta
One- and two-dimensional laser induced fluorescence at oblique incidence
Ioana A Biloiu1,3,
Earl E Scime1 and Costel Biloiu2
1 West Virginia University, Physics Department,
Morgantown, WV 26506, USA
2 Varian Semiconductor Equipment Associates, 35
Dory Road, Gloucester, MA 01930, USA
E-mail:
ibiloiu@mix.wvu.edu
Received 29 August 2008, in final form 3 January
2009
Published 26 February 2009
Online at
stacks.iop.org/PSST/18/025012
Abstract
The diagnostic technique of laser induced
fluorescence (LIF), generalized to the case of oblique laser
injection angle relative to the local magnetic field direction, is
employed for studies of the ion velocity distribution function (IVDF)
in the magnetic expansion region of a helicon plasma source. One-dimensional LIF
measurements reveal key characteristics of the acceleration mechanism responsible for creation of
an ion beam in the expansion regions: a bimodal IVDF comprising a slowly drifting (∼150ms−1)
ion population and a fast ion beam (∼10.7
km s−1).
Two-dimensional LIF, LIF tomography, provides additional insight
regarding the origins of the two ion populations: the nearly
isotropic slow population is a locally created background population whereas the distorted
velocity distribution of the fast population is consistent with an origin upstream of the
measurement location.
References
...
[50] Gulick S L, Stansfield B L,
Abou-Azaleh Z,
Boucher C, Matte J P, Johnston T W and Mochand R 1990
J. Nucl. Mater.
176–177
1059
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2009 No 01 |
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http://www.iop.org/EJ/abstract/0963-0252/17/1/015012
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Ion acoustic wave studies near the
presheath/sheath boundary in a weakly collisional argon/xenon plasma
Lutfi Oksuz et al
2008 Plasma Sources Sci. Technol.
17
015012 (5pp)
doi:10.1088/0963-0252/17/1/015012
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Lutfi Oksuz 1,
Dongsoo Lee
and
Noah
Hershkowitz
Department of Engineering Physics, University of Wisconsin at
Madison, Madison, WI 53706, USA
1
Present address: Department of Physics, Suleyman Demirel
University, Isparta 32260, Turkey.
Abstract
on acoustic
wave (IAW) phase velocities are measured near the sheath/presheath
boundary in a weakly collisional argon/xenon plasma. Wave
profiles versus position are measured using a boxcar averager
with a gate width of 30 ns and CW excitation at 50 or 75 kHz.
Variable gate delays allow measurement of details of the wave
close to the boundary. It is shown that the phase velocity at
the presheath/sheath boundary is approximately twice the phase
velocity in the bulk plasma for both argon and argon/xenon
plasmas, in agreement with a recent calculation (Lee D et
al 2007 Phys. Rev. Lett. 99 155004). This result
indicates each ion's drift velocity at the boundary is equal
to the IAW phase velocity in the bulk plasma.
Print publication: Issue 1
(February 2008)
Received 28 August 2007, in final form
11 October 2007
Published 19 December 2007
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Citations Index
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