The ratio of radial diffusion coefficient to mobility for electrons in helium, argon, air, methane and nitric oxide

Abstract

The ratio of the radial diffusion coefficient to mobility Dr/ mu exp has been measured for the first time in five gases at high E/N (ratio of electric field to gas number density). The range of E/N was as follows: helium 3<or=E/N<or=847 Td; argon 8<or=E/N<or=1271 Td; air 14<or=E/N<or=1412 Td; methane 14<or=E/N<or=5650 Td; nitric oxide 56<or=E/N<or=1412 Td. The Townsend ionization coefficient alpha T/N has also been measured in each gas for the same E/N range.

Experimental study of a low-pressure glow discharge in air in large-diameter discharge tubes: I. conditions for the normal regime of a glow discharge

“…7a). For the air pressure p = 0.6 torr and voltage U dc = 300 V, we obtain E/p = 200 V/(cm torr) near the anode surface, which corresponds to an electron temperature of T e = 6-8 eV [39,40] and agrees with the results of our experiments. At a higher discharge voltage U dc , when the fast electrons accelerated in the cathode sheath reach the anode and the anode glow disappears, the anode voltage drop sharply decreases, which results in a decrease in E/p near the anode surface and a decrease in the electron temperature in the anode sheath.…”

Rf breakdown of low-pressure gas and a novel method for determination of electron-drift velocities in gases

“…Figure 7 shows the electron-drift-velocity values for hydrogen obtained with this technique that are in good agreement with the results obtained with conventional techniques [48][49][50][51].…”

“…Measured and calculated data [48,50,60] show that two characteristic sections are observed for the dependence of the electron-drift velocity on the quantity E/p in the presence of inelastic electron-neutral collisions. For example, for hydrogen with E/p ≈ 10-200 V cm …”

“…Figures 1 and 5, respectively, compare the breakdown curves calculated from the criterion (4) with measured breakdown curves of the rf and longitudinally combined discharges. In calculations we have used the values of V e , D L and D e given in [48][49][50][51][52][59][60][61][62][63][64][65][66] and, to obtain the ionization rate ν i = αV e , we have taken values of the first Townsend coefficient from [42,62,[65][66][67]. Figures 1 and 5 show that there is satisfactory agreement between the curves calculated from equation (4) and the measured ones in the region near and to the righthand side of minima of breakdown curves, the calculated curves being located in regions of higher gas pressures than are the measured ones.…”

High Voltage Switch Using Externally Ionized Plasmas.

“…Since jb and N appear in equation (31) the maximum current gain varies as j. and N vary, in contrast with the attachment dominated limit. We have evaluated equation (31) for the values N = 1.08 x 1020 cm -3 and jb = 1 x 10 -and 0.1 A/cm 2 . The resulting (j/jb)maxvalues are plotted in figure 21.…”