jap banner
  • Volume/Page
  • Keyword
  • DOI
  • Citation
  • Advanced
   
 
 
 

Flickr Twitter iResearch App Facebook

BROWSE VOLUMES

Year Range: 
Search Issue | RSS Feeds RSS
Previous Issue Next Issue

15 Oct 2007

Volume 102, Issue 8, Articles (08xxxx)

Issue Cover Spotlight Figure

J. Appl. Phys. 102, 081301 (2007); http://dx.doi.org/10.1063/1.2799091 (28 pages)

V. V. Afanas’ev and A. Stesmans
Enlarge Image | Read More
Return to All Sections
back to top
RSS Feeds

Surface plasmon excitation at second harmonic over a rippled surface

D. B. Singh and V. K. Tripathi

J. Appl. Phys. 102, 083301 (2007); http://dx.doi.org/10.1063/1.2795575 (4 pages) | Cited 1 time

Online Publication Date: 17 October 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A high power laser of frequency ω incident on a rippled metal surface gives rise to oscillatory electron velocity v2ω at the second harmonic in the skin layer. Its coupling with the surface ripple (modeled as a density ripple) of suitable wave number produces a nonlinear current, driving a surface plasma wave at frequency 2ω.
Show PACS
73.20.Mf Collective excitations (including excitons, polarons, plasmons and other charge-density excitations)
52.35.-g Waves, oscillations, and instabilities in plasmas and intense beams
61.82.Bg Metals and alloys
61.80.Ba Ultraviolet, visible, and infrared radiation effects (including laser radiation)

Beryllium deposition on International Thermonuclear Experimental Reactor first mirrors: Layer morphology and influence on mirror reflectivity

G. De Temmerman, M. J. Baldwin, R. P. Doerner, D. Nishijima, R. Seraydarian, K. Schmid, F. Kost, Ch. Linsmeier, and L. Marot

J. Appl. Phys. 102, 083302 (2007); http://dx.doi.org/10.1063/1.2798389 (7 pages) | Cited 14 times

Online Publication Date: 18 October 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Metallic mirrors will be essential components of the optical diagnostic systems in the International Thermonuclear Experimental Reactor (ITER). Reliability of these systems may be affected by mirror reflectivity changes induced by erosion and/or deposition of impurities (carbon, beryllium). The present study aims to assess the effect of beryllium (Be) deposition on the reflectivity of metallic mirrors and to collect data on the optical quality of these layers in terms of morphology, roughness, etc. Mirrors from molybdenum and copper were exposed in the PISCES-B linear plasma device to collect eroded material from graphite and beryllium targets exposed to beryllium-seeded deuterium plasma. After exposure, relative reflectivity of the mirrors was measured and different surface analysis techniques were used to investigate the properties of the deposited layers. Be layers formed in PISCES-B exhibit high levels of porosity which makes the reflectivity of the Be layers much lower than the reflectivity of pure Be. It is found that if Be deposition occurs on ITER first mirrors, the reflectivity of the coated mirrors will strongly depend on the layer morphology, which in turn depends on the deposition conditions.
Show PACS
52.40.Hf Plasma-material interactions; boundary layer effects
52.55.Fa Tokamaks, spherical tokamaks
52.70.Kz Optical (ultraviolet, visible, infrared) measurements
52.25.Vy Impurities in plasmas

Emission and shock visualization in nonequilibrium nitrogen afterglow plasma

Igor V. Adamovich and J. William Rich

J. Appl. Phys. 102, 083303 (2007); http://dx.doi.org/10.1063/1.2798984 (8 pages) | Cited 2 times

Online Publication Date: 19 October 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
Kinetic modeling of propagating and stationary normal shocks in nonequilibrium nitrogen afterglow plasma is used to simulate the results of shock emission measurements in nitrogen afterglow. Emission intensity overshoot behind the shock predicted by the model is in satisfactory agreement with the experimental results and is consistent with previous analytic estimates. The model demonstrates that the first and the second positive band emission overshoot behind the shock are produced by energy transfer processes among the triplet electronic states of nitrogen generated in the electric discharge. On the other hand, charge separation and ambipolar electric field produced across the shock layer do not result in electron heating and additional electron impact excitation of electronic states. The calculations show that emission overshoot makes possible accurate detection of a stationary shock layer in supersonic flowing afterglow experiments.
Show PACS
52.35.Tc Shock waves and discontinuities
52.25.Os Emission, absorption, and scattering of electromagnetic radiation
52.80.Hc Glow; corona

Cleaning properties of atomic oxygen excited to metastable state 2s22p4(1S0)

E. V. Shun’ko and V. S. Belkin

J. Appl. Phys. 102, 083304 (2007); http://dx.doi.org/10.1063/1.2794857 (14 pages) | Cited 3 times

Online Publication Date: 19 October 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
A possibility to treat surfaces of various materials by bombardment with neutral atomic oxygen excited to the metastable state 2s22p4(1S0), (4.1891 V from the ground) is described. The oxygen dissociation and excitation was developed in plasmas generated in reactors of capacitively coupled dielectric barrier discharge configurations comprised of a quartz or ceramic tube passing throughout two annular electrodes and containing a gas mixture of ∼ 98% Ar with ∼ 2% O2 ionized at the atmospheric pressure by the radio frequency discharge at 13.56 MHz and flowing at about 6 m/s. As shown in the experiments, the transition 2s22p4(1S0)−2s22p4(1D2) with a high degree of probability is responsible for the yellow color of afterglow products, and the lifetime of the metastable state can be as long as 5.4 ms in certain cases, allowing one to separate the excited atomic medium from plasma that it produced. It has been shown that the cleaning process included significant Van der Waals bonds liberation to the depth of several hundred angstroms of surfaces treated, which drastically reduced the percentage of carbon-containing contaminants and changed, to some degree, the chemical structure of surfaces containing chemically bonded oxygen.
Show PACS
52.50.-b Plasma production and heating
52.80.Hc Glow; corona
52.80.Pi High-frequency and RF discharges
52.77.Bn Etching and cleaning
82.33.Xj Plasma reactions (including flowing afterglow and electric discharges)
81.65.Cf Surface cleaning, etching, patterning

Communication through plasma sheaths

A. O. Korotkevich, A. C. Newell, and V. E. Zakharov

J. Appl. Phys. 102, 083305 (2007); http://dx.doi.org/10.1063/1.2794856 (14 pages) | Cited 4 times

Online Publication Date: 23 October 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
We wish to transmit messages to and from a hypersonic vehicle around which a plasma sheath has formed. For long distance transmission, the signal carrying these messages must be necessarily low frequency, typically 2 GHz, to which the plasma sheath is opaque. The idea is to use the plasma properties to make the plasma sheath appear transparent.
Show PACS
52.40.Kh Plasma sheaths
52.40.Db Electromagnetic (nonlaser) radiation interactions with plasma
52.35.Mw Nonlinear phenomena: waves, wave propagation, and other interactions (including parametric effects, mode coupling, ponderomotive effects, etc.)

Loss current minimization during ion extraction from an inductively coupled plasma

Oleksiy Vozniy, Kostyantyn Polozhiy, and Geun Young Yeom

J. Appl. Phys. 102, 083306 (2007); http://dx.doi.org/10.1063/1.2800842 (5 pages) | Cited 1 time

Online Publication Date: 26 October 2007

Full Text: Read Online (HTML) | Download PDF

Show Abstract
In ion sources with a grid-type acceleration system, the output current often decreases with increasing power at a constant extraction voltage despite the fact that the carrier density inside the source increases linearly. At this point, the loss and output currents have the same magnitude. This paper proposes a mechanism for loss current minimization when restrictions are placed on the beam focusing efficiency with increasing rf power. The influence of the plasma potential on the magnitude of the loss current was examined. The beam intensity was found to increase considerably when the plasma potential was sufficiently high to suppress sheath curvature growth.
Show PACS
52.50.Dg Plasma sources
Return to All Sections
Close

Google Calendar

ADVERTISEMENT

Go to AIP Home   © AIP Publishing LLC
close