Corner-Expansion Flow of Ionized Argon

1971 ◽  
Vol 49 (21) ◽  
pp. 2671-2679 ◽  
Author(s):  
O. Igra ◽  
I. I. Glass
Keyword(s):  
Room Temperature ◽  
Electron Number Density ◽  
Laser Interferometry ◽  
Total Density ◽  
Number Density ◽  
Dual Frequency ◽  
Electron Number ◽  
Recombination Rate Constant ◽  
Initial Shock ◽  
Frequency Laser

The recombination rate constant for ionized argon as a function of temperature was determined by using dual-frequency laser interferometry to measure total density and electron number density in a 15° corner-expansion flow. The flow was induced by a normal shock wave in a 4 in. × 7 in. (10.2 cm × 17.8 cm) hypervelocity shock tube over a range of initial shock Mach numbers [Formula: see text] and pressures [Formula: see text] Torr at room temperature T1 ~ 300 °K, with impurity levels less than 150 parts per million.

scholarly journals Influence of water vapour on the height distribution of positive ions, effective recombination coefficient and ionisation balance in the quiet lower ionosphere

2014 ◽  
Vol 32 (3) ◽  
pp. 207-222 ◽  
Author(s):  
V. Barabash ◽  
A. Osepian ◽  
P. Dalin
Keyword(s):  
Water Vapour ◽  
Electron Density ◽  
Electron Number Density ◽  
Lower Ionosphere ◽  
Recombination Coefficient ◽  
Height Distribution ◽  
Number Density ◽  
Electron Number ◽  
Water Vapour Concentration ◽  
Vapour Concentration

Abstract. Mesospheric water vapour concentration effects on the ion composition and electron density in the lower ionosphere under quiet geophysical conditions were examined. Water vapour is an important compound in the mesosphere and the lower thermosphere that affects ion composition due to hydrogen radical production and consequently modifies the electron number density. Recent lower-ionosphere investigations have primarily concentrated on the geomagnetic disturbance periods. Meanwhile, studies on the electron density under quiet conditions are quite rare. The goal of this study is to contribute to a better understanding of the ionospheric parameter responses to water vapour variability in the quiet lower ionosphere. By applying a numerical D region ion chemistry model, we evaluated efficiencies for the channels forming hydrated cluster ions from the NO+ and O2+ primary ions (i.e. NO+.H2O and O2+.H2O, respectively), and the channel forming H+(H2O)n proton hydrates from water clusters at different altitudes using profiles with low and high water vapour concentrations. Profiles for positive ions, effective recombination coefficients and electrons were modelled for three particular cases using electron density measurements obtained during rocket campaigns. It was found that the water vapour concentration variations in the mesosphere affect the position of both the Cl2+ proton hydrate layer upper border, comprising the NO+(H2O)n and O2+(H2O)n hydrated cluster ions, and the Cl1+ hydrate cluster layer lower border, comprising the H+(H2O)n pure proton hydrates, as well as the numerical cluster densities. The water variations caused large changes in the effective recombination coefficient and electron density between altitudes of 75 and 87 km. However, the effective recombination coefficient, αeff, and electron number density did not respond even to large water vapour concentration variations occurring at other altitudes in the mesosphere. We determined the water vapour concentration upper limit at altitudes between 75 and 87 km, beyond which the water vapour concentration ceases to influence the numerical densities of Cl2+ and Cl1+, the effective recombination coefficient and the electron number density in the summer ionosphere. This water vapour concentration limit corresponds to values found in the H2O-1 profile that was observed in the summer mesosphere by the Upper Atmosphere Research Satellite (UARS). The electron density modelled using the H2O-1 profile agreed well with the electron density measured in the summer ionosphere when the measured profiles did not have sharp gradients. For sharp gradients in electron and positive ion number densities, a water profile that can reproduce the characteristic behaviour of the ionospheric parameters should have an inhomogeneous height distribution of water vapour.

Characteristics of a resonant iris microwave-induced nitrogen plasma

2016 ◽  
Vol 31 (5) ◽  
pp. 1097-1104 ◽  
Author(s):  
Daniel A. Goncalves ◽  
Tina McSweeney ◽  
George L. Donati
Keyword(s):  
Electron Number Density ◽  
Nitrogen Plasma ◽  
Number Density ◽  
Electron Number ◽  
Temperature Electron ◽  
Mip Oes

Temperature, electron number density and robustness profiles of a N2 plasma contribute for more sensitive and accurate MIP OES determinations.

scholarly journals Excitation and analytical characteristics of an ethanol loaded U-shaped arc

2003 ◽  
Vol 68 (2) ◽  
pp. 109-118 ◽  
Author(s):  
Marija Raskovic ◽  
Ivanka Holclajtner-Antunovic ◽  
Mirjana Tripkovic ◽  
Dragan Markovic
Keyword(s):  
Spectral Line ◽  
Electron Number Density ◽  
Ethanol Solution ◽  
Number Density ◽  
Electron Number ◽  
Plasma Parameters ◽  
Line Intensities ◽  
Ethanol Addition ◽  
Plasma Characteristics ◽  
Dc Arc

The effect of the ethanol load on the discharge and analytical parameters of an argon stabilized U-shaped DC arc has been recorded. Measurements of the radial distribution of the apparent temperatures and the electron number density of the DC plasma showed that ethanol addition causes a decrease in both plasma parameters. The changes in the plasma characteristics, as well as in transport and atomisation processes of the analyte cause a general change in the spectral line intensities, which depends on the physical characteristics of the analyte and the quantity of ethanol loaded into the plasma. Improved detection limits were obtained for V and Mn when a 10%(v/v) water?ethanol solution was nebulized into the plasma.

Jeans-Alfvén instability in quantum dusty magnetoplasmas

2017 ◽  
Vol 83 (1) ◽  
Author(s):  
M. Jamil ◽  
A. Rasheed ◽  
M. Amir ◽  
G. Abbas ◽  
Young-Dae Jung
Keyword(s):  
Significant Contribution ◽  
Electron Number Density ◽  
Fluid Model ◽  
Low Frequency ◽  
Momentum Balance ◽  
Number Density ◽  
Electron Number ◽  
Momentum Balance Equation ◽  
Quantum Plasmas ◽  
Jeans Instability

The Jeans instability is examined in quantum dusty magnetoplasmas due to low-frequency magnetosonic perturbations. The fluid model consisting of the momentum balance equation for quantum plasmas, Poisson’s equation for the gravitational potential and Maxwell’s equations for electromagnetic magnetosonic perturbations is solved. The numerical analysis elaborates the significant contribution of magnetic field, electron number density and variable dust mass to the Jeans instability.

Calculated electron number density profiles for the aeroassist flight experiment

1992 ◽  
Vol 29 (5) ◽  
pp. 621-626 ◽  
Author(s):  
Robert B. Greendyke ◽  
Peter A. Gnoffo ◽  
R. Wes Lawrence
Keyword(s):  
Electron Number Density ◽  
Number Density ◽  
Electron Number ◽  
Density Profiles ◽  
Flight Experiment

Optical Detection of Laser-Induced Ionization: A Study of the Time Decay of Strontium Ions in the Air-Acetylene Flame

1986 ◽  
Vol 40 (8) ◽  
pp. 1085-1092 ◽  
Author(s):  
G. C. Turk ◽  
N. Omenetto
Keyword(s):  
State Transition ◽  
Electron Number Density ◽  
Dye Laser ◽  
Number Density ◽  
Fast Decay ◽  
Ion Chemistry ◽  
Electron Number ◽  
Slow Decay ◽  
Optical Probing ◽  
Density Of Electrons

Strontium atoms in the air-acetylene flame are directly photoionized in two steps provided by one dye laser tuned at the resonance ground-state transition (460.733 nm) and by the excimer pump beam at 308 nm, partially split from the amplifier section of the dye laser. The ions produced are then monitored by a third laser beam, colinear and counterpropagating in the flame, tuned to an ionic fluorescence transition and delayed in time with respect to the ionizing beams. In this way a fast decay, which is not affected by variations in the electron number density in the flame and therefore attributed to ion chemistry, and a slow decay, due to recombination, could clearly be observed. The fast decay is affected by variations in the flame stoichiometry and the slow decay by the number density of electrons in the flame, as shown by the addition of varying concentrations of an easily ionized element like caesium. The advantages of this optical probing of the laser-induced ionization in flames are discussed.

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