|
Articles
/ Dissertation
with Citations
to Z. Abou-Assaleh |
|
|
|
|
2005-1 |
|
|
Journal of Nuclear Materials
Volumes 337-339 , 1 March 2005, Pages 246-250 |
|
|
|
Modification of atomic physics rates due to nonlocal electron
parallel heat transport in divertor plasmas
|
|
F. Allaisa,
 ,
J.P. Mattea,
,
 ,
F. Alouani-Bibia, C.G. Kima,
D.P. Stotlerb and T.D. Rognlienc
aINRS-Énergie, Matériaux et Télécommunications, 1650
boul. Lionel Boulet, Varennes, Québec, Canada J3X 1S2
bPrinceton Plasma Physics Laboratory, Princeton, NJ,
USA
cLawrence Livermore National Laboratory, Livermore, CA,
USA
Available online 24 December 2004.
Abstract
The effect of steep temperature gradients on the rate of
ionization of atomic hydrogen is studied numerically with the
electron kinetic code ‘FPI’ [Phys. Rev. Lett. 72 (1994) 1208]. A
set of cross sections [‘Atomic and Plasma-Material Interaction
data for fusion’. Supplement to the journal Nucl. Fusion 4
(1993)] has been used which gives the same rates of radiation,
ionization and recombination as in the well known edge modeling
codes ‘UEDGE’ and ‘DEGAS’ for Maxwellian electron energy
distribution functions. For this purpose, 30 energy levels are
included in the computation, as stepwise ionization is dominant.
The enhancement of the ionization rate by non-Maxwellian effects
in the colder part of the plasma is significant.
Keywords: Collisional radiative model;
Divertor modelling; Kinetics effects; Parallel transport; UEDGE
|
|
|
|
2005-2 |
|
|
|
doi:10.1016/j.tsf.2005.08.114 |
Thin
Solid Films
Volumes 506-507 , 26 May 2006, Pages 674-678
The Joint Meeting of 7th APCPST (Asia Pacific Conference on Plasma
Science and Technology) and 17th SPSM (Symposium on Plasma Science
for Materials) - 7th APCPST/17th SPSM |
|
|
|
Ion flow and sheath physics studies in multiple ion species
plasmas using diode laser based laser-induced fluorescence |
G.D. Severn1,
a,, Xu Wangb,
Eunsuk Kob, N. Hershkowitzb,
M.M. Turnerc and R. McWilliamsd
aDepartment of Physics, University of San Diego, San
Diego, CA 92110, USA
bEngineering Physics Department, University of
Wisconsin-Madison, Madison, WI 53706, USA
cNational Center for Plasma Science and Technology,
Dublin City University, Glasnevin, Dublin 9, Ireland
dDepartment of Physics and Astronomy, University of
California, Irvine, CA 92049, USA
Available online 27 December 2005.
|
Abstract
Diode lasers have proved to be a valuable light source for
laser-induced fluorescence (LIF) measurements for plasma science
since the early 1990s, and they have recently improved the state
of the art of measuring ion flow from ion velocity distribution
functions (ivdfs) at the sheath–presheath boundary in single and
multiple ion species plasmas. In the case of a low temperature two
ion species plasma (ArI + HeI), we were the first to show
experimentally that ion species may reach the sheath edge flowing
at a very different speed than that expected from the single
species Bohm Criterion (ArII ions exceed the individual Bohm flow
speed by almost a factor of 2 at the sheath edge). Simulation
results are found to agree. Diode laser technology relevant to LIF
measurements in multiple ion species plasmas is discussed with the
aim of addressing outstanding problems in sheath formation in such
plasmas. |
|
|
|
2005-3 |
|
|
|
Parallel heat flux limits in the
tokamak scrape-off layer
W Fundamenski 2005
Plasma Phys. Control. Fusion
47 R163-R208 doi:10.1088/0741-3335/47/11/R01
W Fundamenski
Euratom/UKAEA Fusion Association, Culham Science Centre,
Abingdon, Oxon, UK
Abstract. It is well
known that the classical Spitzer–Harm–Braginskii expression
for the parallel plasma heat flux breaks down in the long mean
free path limit, relevant to many practical applications, most
crucially power exhaust via the tokamak scrape-off layer
(SOL). This problem is usually addressed by limiting the heat
flux to some fraction of the free streaming value, with
constants of proportionality ασ, where σ ∈ {e,i},
ranging from 0.03 to 3. The following paper presents a brief
overview of the problem, compares the results of various
kinetic studies, suggests the optimal values of ασ
for use in plasma–fluid codes, and examines the impact of
these values on 2D SOL simulations using the EDGE2D transport
code. In this context, gyro-kinetic parallel heat flux
expressions for both electrons and ions are derived from the
generalized transport equations—an improved version of Grad's
21-moment approach—and their implications to tokamak modelling
are discussed.
Print
publication: Issue 11 (November 2005)
Received 6 December 2004, in final form
28 July 2005
Published 5 October 2005
http://www.iop.org/EJ/abstract/0741-3335/47/11/R01/
http://ej.iop.org/links/rTqyxnIWm/SnTZP6Wg2xGkAZxsav5vpA/psst5_1_022.pdf |
|
|
|
|
|
2005-4 |
|
|
|
Scrape-off layer physics: an
introduction (to be published)
Ralf Schneider,
Max-Planck-Institut f¨ur Plasmaphysik, EURATOM association,
Garching, Germany
http://www.ipp-garching.mpg.de/~dpc/rfs.pdf |
|
|
|
|
|
2005-5 |
|
|
Phys. Plasmas 12, 063104 (2005) (8
pages)
Supersonic propagation of ionization waves in an underdense,
laser-produced plasma
-
C. Constantin,
C. A. Back,
K. B. Fournier,
G. Gregori,
O. L. Landen,
S. H. Glenzer,
and
E. L. Dewald
- Lawrence
Livermore National Laboratory, 7000 East Avenue, Livermore,
California 94550
-
M. C. Miller
- Los
Alamos National Laboratory, Los Alamos, New Mexico 87545
(Received 11 November 2004;
accepted 8 April 2005; published online 6 June 2005)
A laser-driven
supersonic ionization wave propagating through a millimeter-scale
plasma of
subcritical density up to 2–3 keV electron temperatures was
observed. Propagation velocities initially ten times
the sound speed were measured by means of time-resolved
x-ray imaging diagnostics. The measured ionization wave
trajectory is modeled analytically and by a two-dimensional
radiation-hydrodynamics code. The comparison to the
modeling suggests that nonlocal heat transport effects
may contribute to the attenuation of the heat-wave propagation.
©2005 American Institute of Physics |
|
|
|
|
|
2005-6 |
|
|
|
L
Oksuz et al 2005
Plasma Sources Sci. Technol.
14 201-208
Plasma, presheath, collisional sheath
and collisionless sheath potential profiles in weakly ionized,
weakly collisional plasma
L Oksuz1
and
N Hershkowitz
Department of Engineering Physics, University of
Wisconsin-Madison, USA
1 Current address: Plasma Research Laboratory, Dublin
City University, Dublin, Republic of Ireland.
Received 30
September 2003
Published 7 February 2005
Print publication: Issue 1 (February 2005)
Abstract. Potential
variations in bulk plasma, presheath and sheath describe the
plasma potential profile responsible for ion acceleration out of
weakly ionized, weakly collisional plasma. Experiments with
emissive probes, Langmuir probes, laser induced fluorescence (LIF)
and Mach probes in a multi-dipole plasma show that the presheath
potential near a negatively biased plate scales as
and is insensitive to the value of the plate bias. Plasma
parameters were chosen so that ε = λD/λ
0.02 → 0.06 and 0.2 < λ/L <0.6, where λ is the ion–neutral mean
free path, λD is the Debye length and L is the plasma
length. A Child–Langmuir-like sheath with width scaling as λD(e /Te)3/4
with a Te/λD initial boundary electric
field has been measured. A transition region, in which the
plasma starts to deviate from being quasi-neutral, is observed
between the presheath and the Child–Langmuir sheath. The
transition region is approximately 2λD or λ1/5λd4/5.
Mach probe data, calibrated by LIF data, suggest that the
average ion velocity reaches the Bohm velocity inside the
transition region and significantly exceeds the Bohm velocity at
the Child–Langmuir sheath/transition boundary.
doi:10.1088/0963-0252/14/1/022
URL: http://stacks.iop.org/0963-0252/14/201
PII: S0963-0252(05)93759-6
|
|
http://ej.iop.org/links/q38/g,zrlJAHsg6q,iou3NUz1w/psst5_1_022.pdf |
|
|
|
2005-7 |
|
|
[14] S. L. Gulick, B. L. Stansfield, Z. Abouassaleh,
C. Boucher, J. P. Matte,.
T. W. Johnston, and R. Marchand, “Measurement of pre-sheath flow
ve- ...
ieeexplore.ieee.org/iel5/27/30693/
01420601.pdf?arnumber=1420601 |
|
|
Presheath environment in weakly
ionized single and multispecies plasmas
Hershkowitz, N. Ko, E.
Xu Wang Hala, A.M.A.
Center for Plasma-Aided Manuf., Univ. of Wisconsin, Madison, WI,
USA;
This paper appears in:
Plasma Science, IEEE Transactions on
Publication Date: April 2005
Volume: 33,
Issue: 2, Part 2
On page(s): 631- 636
ISSN: 0093-3813
INSPEC Accession Number: 8398049
Digital Object Identifier: 10.1109/TPS.2005.844608
Posted online: 2005-04-18 09:10:46.0
|
The presheath located near boundaries in weakly ionized plasmas is
a rich environment in which charge exchange, and ion-ion streaming
instabilities combine to establish the electric fields that
accelerate ions to close to the Bohm velocity at the sheath/presheath
boundary. Charge exchange sets the presheath scale length in
weakly collisional plasma, in which ionization can be neglected.
The transition of mobility limited ion flow near the bulk plasma
to free fall motion close to the plate for single species plasmas
is explored. Measurements in argon-helium multidipole plasmas of
plasma potential with emissive probes and ion energy distribution
functions with laser induced fluorescence are presented. These
data show that the argon ions are speeded up by the presheath
electric fields, argon ions are heated, and ion-ion instability is
present as ions approach the boundary. |
|
|
|
http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?tp=&arnumber=1420601&isnumber=30693 |
|
|
|
|
| |
|
|
|
|
|
|
|
|
Articles
/
Dissertation |
|
with Citations to |
|
Z. Abou-Assaleh |
|
|
|
Theoretical Plasma
Physics |
|
&
Controlled Thermonuclear Fusion Energy |
|
|
Dissertations |
|
|
|
Books |
|
|
|
|
Articles |
|
|
|
|
|
|
|
|
