scholarly journals Electron Drift And Diffusion In Deuterium At 293°K

1966 ◽  
Vol 19 (6) ◽  
pp. 805 ◽  
Keyword(s):  
Diffusion Coefficient ◽  
Drift Velocity ◽  
Electron Drift ◽  
And Diffusion

The drift velocity and the ratio of diffusion coefficient to mobility have been measured for electrons in deuterium at 293�K over the ranges 0�006 � E/p � 5�0 and 0�006 � E/p � 2�0 respectively. The results are compared with those of other workers.

scholarly journals Computer Simulation of an Electron Swarm at low E/p in Helium

1974 ◽  
Vol 27 (1) ◽  
pp. 59 ◽  
Author(s):  
AI McIntosh
Keyword(s):  
Computer Simulation ◽  
Diffusion Coefficient ◽  
Cross Section ◽  
Electron Energy Distribution Function ◽  
Recent Theory ◽  
Electron Drift ◽  
Longitudinal Diffusion ◽  
Transverse Diffusion ◽  
And Diffusion ◽  
Momentum Transfer Cross Section

A computer simulated electron swarm at E/P293 = 1�0 V cm -1 tore 1 in a model gas has been used to examine the validity of a recent theory of electron drift and diffusion. The computed results are in agreement with well-established theories for the electron energy distribution function, drift velocity and transverse diffusion coefficient, and confirm that, for a constant momentum transfer cross section, the longitudinal diffusion coefficient is approximately half the transverse coefficient. However, significant differences have been found between the computed swarm and the predictions of the theory of Huxley (1972). In particular, over the time scale considered, the electron swarm is not symmetric about its centroid but is spatially anisotropic in such a way that it could appropriately be described as 'pear shaped'.

The motion of slow positive ions in gases - Drift and diffusion of ions in hydrogen

1966 ◽  
Vol 259 (1100) ◽  
pp. 339-354 ◽  
Keyword(s):  
Diffusion Coefficient ◽  
Leakage Current ◽  
Drift Velocity ◽  
Leakage Currents ◽  
Initial Design ◽  
Positive Ions ◽  
New Apparatus ◽  
Present Part ◽  
And Diffusion

In part II, the initial design of an apparatus to measure both the drift velocity W and the ratio of drift velocity to diffusion coefficient ( W/D ) for positive ions in gases was described. Measurements of W in argon and nitrogen using this apparatus were discussed in parts II and III, but it was shown that large leakage currents prevented the measurement of the ratio W/D . As a result of investigations of the leakage current, the apparatus was redesigned, and the purpose of the present part is to describe this new apparatus and to discuss the results obtained in hydrogen.

scholarly journals Electron Swarm Transport Through Low Pressure Noble Gases

1992 ◽  
Vol 45 (2) ◽  
pp. 185 ◽  
Author(s):  
G Dall’Armi ◽  
KL Brown ◽  
PH Purdie ◽  
J Fletcher
Keyword(s):  
Diffusion Coefficient ◽  
Drift Velocity ◽  
Noble Gases ◽  
Electron Drift Velocity ◽  
Current Work ◽  
Electron Drift ◽  
Longitudinal Diffusion ◽  
Transient Technique ◽  
Voltage Transient ◽  
Helium Neon

The electron drift velocity, the longitudinal diffusion coefficient and the electron ionisation coefficient have been measured in helium, neon, argon and krypton using the integrated voltage transient technique. Whilst the present data agree substantially with previous determinations at those values of E / N at which they overlap, the current work represents a marked extension of the range of E/N covered for We and NDL in most of the gases investigated.

scholarly journals Electron Drift and Diffusion in Parahydrogen at 77°K

1968 ◽  
Vol 21 (5) ◽  
pp. 637 ◽  
Author(s):  
RW Crompton ◽  
AI McIntosh
Keyword(s):  
Diffusion Coefficient ◽  
Energy Distribution ◽  
Vibrational Excitation ◽  
Electron Drift ◽  
Thermal Region ◽  
Dominant Process ◽  
Series Of Experiments ◽  
Normal Hydrogen ◽  
The Difference ◽  
And Diffusion

This paper reports a series of experiments to measure electron diffusion and drift in pure parahydrogen at 77° K. Tables of data are given for the electron drift velocity W in the range 1.2 X l0−19 ≤ E/N ≤ 9.5 x l0−17 V cm2 and for the ratio of diffusion coefficient to mobility D/μ for 2 X 10−20 ≤ E/N ≤ 6 X 10−17 V cm2. As expected, these data are indistinguishable from the data for normal hydrogen in the thermal region and at the higher values of E/N where vibrational excitation is the dominant process controlling the electron energy distribution. However, at intermediate values of E/N, the values of W and D/μ differ by more than 10 and 20% respectively from the corresponding values in normal hydrogen, demonstrating the influence of the difference in the statistical weights of the rotational levels in the two gases.

scholarly journals On the Swarm Method for Determining the Ratio of Electron Drift Velocity to Diffusion Coefficient

1962 ◽  
Vol 15 (4) ◽  
pp. 451 ◽  
Author(s):  
RW Crompton ◽  
RL Jory
Keyword(s):  
Diffusion Coefficient ◽  
Drift Velocity ◽  
Thermal Equilibrium ◽  
Electron Drift Velocity ◽  
Electron Drift ◽  
Use Of Data ◽  
Factors Influencing ◽  
Number Of Factors ◽  
Accuracy Of Measurements ◽  
Range Of Values

The use of data from swarm experiments for electron energies approaching those corresponding to thermal equilibrium demands results of greater precision than has hitherto been available. In order to examine the possibility of producing such data, the swarm method for detennining W / D has been extensively examined over a range of values of the parameter E / p where the agreement between the results of recent investigations is not good. A number of factors influencing the accuracy of measurements of this type are discussed. The results for hydrogen which are presented are considered to be subject to an error of less than 1 %.

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