Duration of energy storage following a discharge in xenon

1970 ◽  
Vol 48 (15) ◽  
pp. 1817-1829 ◽  
Author(s):  
P. R. Timpson ◽  
J. M. Anderson
Keyword(s):  
Diffusion Coefficient ◽  
Energy Storage ◽  
Metastable State ◽  
Exponential Decay ◽  
Resonance Line ◽  
High Pressures ◽  
Ambipolar Diffusion ◽  
Ion Recombination ◽  
Low Pressures ◽  
Positive Ion

It has been shown that the afterglow following a discharge in xenon consists of two parts: (1) the resonance line, whose intensity initially decays exponentially in agreement with Holstein's theory; (2) an accompanying distributed radiation, experimentally a continuum, extending to about 1900 a.u. The intensity of this continuum decays exponentially at the same rate as the population of the lower metastable state at all wavelengths and each pressure studied. All departures from an exponential decay seem to be caused by repopulation of states by ionic recombination and are current dependent. Electron disappearance is due to ambipolar diffusion at low pressures and ion recombination at high pressures. The value of the ambipolar diffusion coefficient indicates that the afterglow positive ion is Xe2+ for pressures greater than 0.3 Torr. No phenomena which could be due to interchange of population between metastable states have been found in xenon.

THE LOSS OF FREE ELECTRONS IN IRRADIATED AIR

1963 ◽  
Vol 41 (4) ◽  
pp. 625-631 ◽  
Author(s):  
B. G. Young ◽  
A. W. Johnson ◽  
J. A. Carruthers
Keyword(s):  
High Pressures ◽  
Irradiation Time ◽  
High Energy ◽  
Free Electrons ◽  
Loss Mechanism ◽  
High Energy Electrons ◽  
Ion Recombination ◽  
Three Body ◽  
Microwave Probe ◽  
Low Pressures

The loss of free electrons in air, nitrogen, and oxygen is studied as a function of pressure by continuously irradiating the gases with high-energy electrons and measuring the equilibrium electron densities with a microwave probe. At low pressures (1–10 mm Hg) electrons are lost by free diffusion to the chamber walls before cooling. At intermediate pressures (10–100 mm Hg) electrons cool rapidly without loss to thermal energy and then disappear by three-body attachment in air and oxygen, and by electron–ion recombination in nitrogen. At high pressures (100–1000 mm Hg) the electron density increases with irradiation time and the controlling loss mechanism is uncertain.

scholarly journals Mobility of the positive and negative ions in gases at high pressure

1912 ◽  
Vol 86 (584) ◽  
pp. 154-162 ◽  
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Mathematical Expression ◽  
Negative Ions ◽  
Negative Ion ◽  
Positive Ions ◽  
Low Pressures ◽  
Positive Ion ◽  
Reduced Pressures

The velocity of ions in gases at reduced pressures was first investigated by Rutherford and by Langevin. Recently the author and others have carried out similar investigations. The results of these investigations show that for the negative ions in air the product of the mobility and the pressure is constant for pressures ranging from 760 mm. to 200 mm. of mercury, but with further reduction the product increases with the reduction of pressure, this increase becoming very great at low pressures. For the positive ions in air the product of the mobility and pressure is constant for pressures investigated between 760 mm. and 3 mm. of mercury. Similar results were obtained for the mobilities of the ions in other gases. The results show that if the ion is an aggregation of molecules, this aggregation becomes, at low pressures, less complex in the ease of the negative ion, while in the ease of the positive ion it persists down to 3 mm. of mercury. The purpose of the present research was the study of the mobilities of both kinds of ions in gases at high pressures. The method of investigation is based on the mathematical expression, developed by Prof. Rutherford, for the current between two plates, assuming that a very intense ionisation exists near the surface of one of the electrodes.

THE DECAY OF THE POPULATIONS OF METASTABLE ATOMS AND IONS FROM THE SAME D-C. DISCHARGE IN NEON

1957 ◽  
Vol 35 (8) ◽  
pp. 941-953 ◽  
Author(s):  
B. C. Blevis ◽  
J. M. Anderson ◽  
R. W. McKay
Keyword(s):  
Pressure Range ◽  
Principal Factor ◽  
Measurable Effect ◽  
Population Changes ◽  
Electron Population ◽  
Diffusion Constants ◽  
Ion Recombination ◽  
Low Pressures ◽  
Limits Of Error ◽  
Positive Ion

Measurements of electron density and of the population of the 3P2 metastable state have been made following cessation of a d-c. discharge in neon gas. Determinations of these populations were made under identical conditions at accurately determined times after termination of the discharge and decay curves were plotted for a pressure range from 0.5 to 12.0 mm. Hg. At low pressures, where diffusion is the principal factor in the decay, both curves are exponential and show the same mean life, within the limits of error. Values of the diffusion constants obtained from these curves are consistent with the results of previous workers in both fields. At higher pressures the metastable decay remains exponential while the reciprocal of the electron population changes linearly with time. In general, the two decays are unrelated. Only at the highest pressure studied, and in this case for only the first half millisecond, was a measurable effect of positive ion recombination found in the metastable population curve.

Rekombination und Diffusion in Abhängigkeit von der Elektronentemperatur eines zerfallenden Neonplasmas

1965 ◽  
Vol 20 (3) ◽  
pp. 450-457
Author(s):  
Walther Hess
Keyword(s):  
Diffusion Coefficient ◽  
Electron Temperature ◽  
Power Level ◽  
Ambipolar Diffusion ◽  
Microwave Cavity ◽  
Recombination Coefficient ◽  
Ion Recombination ◽  
Lower Temperature ◽  
Lower Temperature Region ◽  
Gas Pressures

The object of this paper is an experimental investigation of the electron temperature dependence of the ambipolar diffusion coefficient as well as the electron-ion recombination coefficients in the afterglow of plasmas produced in neon. By means of a microwave-cavity technique the electron density was measured as a function of time during the afterglow period of a d. c. discharge while at the same time the electron energy was increased by the power level of a microwave signal. It is found that the ambipolar diffusion coefficient Da increases with increasing electron temperature Te following the well-known relation: Da ∞ (1 + Te/Tg) , while the recombination coefficient a decreases with increasing electron temperature. The dependence of a on electron temperature is found to be: α ∞ Te-0,4 from 900 ° K to 2400 °K , while a weaker dependence in the range of α ∞ Te-0,25 was measured in the lower temperature region from 300 °K to 600 °K . At 300 °K the recombination coefficient in neon is found to be α = 2.0 · 10-7 cm3 sec-1. All measurements were done at electron densities of ~ 109/cc and gas pressures of 1 mm Hg (diffusion) and 20 mm Hg (recombination).

scholarly journals Comparison of gas dehydration methods based on energy consumption

2016 ◽  
Vol 20 (2) ◽  
pp. 253-258
Author(s):  
B.S. Kinigoma ◽  
G.O. Ani
Keyword(s):  
Energy Consumption ◽  
Natural Gas ◽  
High Pressures ◽  
Energy Requirement ◽  
Chemical Properties ◽  
Triethylene Glycol ◽  
Design Engineers ◽  
Natural Gas Dehydration ◽  
Physical And Chemical ◽  
Low Pressures

This study compares three conventional methods of natural gas (Associated Natural Gas) dehydration to carry out the dehydration process and suitability of use on the basis of energy requirement. These methods are Triethylene Glycol (TEG) absorption, solid desiccant adsorption and condensation. Analyses performed were based on dehydration of Natural Gas saturated with 103Nm3/h water content at a temperature range of -10O C to 30oC, and gas pressure variation between 7MPa and 20MPa. This analysis and study showed that energy required for all three processes decreases with increase in pressure, but condensation dehydration requires the least energy at high pressures. Results obtained shows that, both at high pressures and low pressures, TEG dehydration is most suitable and in cases where very low Tdew is required, solid desiccant adsorption is preferable. In conclusion, the findings in this paper will aid natural gas process design engineers to decide on what method to use base  on energy consumption and on the physical and chemical properties of the final products.Keywords: Dehydration, Absorption, Desiccant, Condensation, Triethylene Glycol (TEG)

scholarly journals Relationship between the Transport Coefficients of Polar Substances and Entropy

Entropy ◽  
2019 ◽  
Vol 22 (1) ◽  
pp. 13
Author(s):  
Ivan Anashkin ◽  
Sergey Dyakonov ◽  
German Dyakonov
Keyword(s):  
Experimental Data ◽  
Thermal Conductivity ◽  
Diffusion Coefficient ◽  
High Pressures ◽  
Thermal Conductivity Coefficient ◽  
Good Description ◽  
Transport Coefficients ◽  
Viscosity Coefficient ◽  
Wide Region ◽  
Good Agreement

An expression is proposed that relates the transport properties of polar substances (diffusion coefficient, viscosity coefficient, and thermal conductivity coefficient) with entropy. To calculate the entropy, an equation of state with a good description of the properties in a wide region of the state is used. Comparison of calculations based on the proposed expressions with experimental data showed good agreement. A deviation exceeding 20% is observed only in the region near the critical point as well as at high pressures.

scholarly journals On the validity of the ambipolar diffusion assumption in the polar mesopause region

2008 ◽  
Vol 26 (11) ◽  
pp. 3439-3443 ◽  
Author(s):  
A. P. Ballinger ◽  
P. B. Chilson ◽  
R. D. Palmer ◽  
N. J. Mitchell
Keyword(s):  
Ambient Temperature ◽  
Decay Time ◽  
Ambipolar Diffusion ◽  
Northern Sweden ◽  
Mesopause Region ◽  
Decay Times ◽  
Meteor Trail ◽  
Temperature And Pressure ◽  
Ion Recombination ◽  
Meteor Trails

Abstract. The decay of underdense meteor trails in the polar mesopause region is thought to be predominantly due to ambipolar diffusion, a process governed by the ambient temperature and pressure. Hence, observations of meteor decay times have been used to indirectly measure the temperature of the mesopause region. Using meteor observations from a SKiYMET radar in northern Sweden during 2005, this study found that weaker meteor trails have shorter decay times (on average) than relatively stronger trails. This suggests that processes other than ambipolar diffusion can play a significant role in trail diffusion. One particular mechanism, namely electron-ion recombination, is explored. This process is dependent on the initial electron density within the meteor trail, and can lead to a disproportionate reduction in decay time, depending on the strength of the meteor.

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