Asymptotic Electric Microfield Distributions in Low-Frequency Component Plasmas

Abstract

GAS PUMPING IN Ar DISCHARGEdependence of hp/L on M may be more complicated than Eq. (A1) indicates. Equation (A9) predicts hp/L ccI/p, just as Ruttenauer observed, but unfortunately the use of the highpressure form for Vs in Eq. (A8) Lwhich leads to Eq. (A9) ] cannot be justiled in the case of helium and.neon. The critical value of pR separating the highpressure and low-pressure forms for V3 may be written pR=1.06V, (p in Torr, R in mm, V, in V) in argon. However, according to Francis, V, ranges from 5 to 15 V for helium and neon in Ruttenauer's experimen. ts. (Such high electron temperatures have been observed by Labuda and Gordons' in helium-neon discharges. ) Physically, this then means that the radial 6elds are much greater in helium and. neon than in argon at similar values of pR, so that ion radial drift velocities are considerably greater in the lighter gases at a given value of pR.Thus V3 will still have its "small x" form at some values of pR in argon but its "large x" form at the same values of pR in neon or helium. (1964).should occur at pR=2.02V, in neon pR=2. 22V, in, helium (p in, Torr, R in mm, V, in V). If the high values of electron temperature previously mentioned occurred in Ruttenauer's tubes, then it is clear that the appropriate form for Vs in Eq. (A"/) should be the low pressure form (the large-x limit). As previously remarked in the case of argon, the large-x limit of V~is pressure-independent, so that the 1/p dependence found by Ruttenauer cannot be accounted for in this case.The resolution of this remaining disagreement must await further work. Perhaps the electron temperature in Ruttenauer's range of current and pressures is lower than estimated here, in which case Eq. (A9) would still be applicable and would account for his measurements in helium and neon. Perhaps other pumping processes at work in these gases make Va an incomplete description of the pumping mechanism. Or perhaps, because of the small currents used by Ruttenauer, changes in electron temperature and axial field as a function of current obscured a true interpretation of the pressure dependence over the limited range of parameters he used in his work on helium and neon.A recently developed collective-coordinate technique is employed to calculate electric micro6eld distribution functions P(e) for low-frequency-component plasmas. Values of e considered range from 10 to 50, and both neutral-point and charged-point cases are treated. Comparison is made with appropriate asymptotic expressions.

Stark broadening tables for the helium I 447.1 line

“…As already said, the ST treatment separates that perturber field into two statistically independent parts. The first, the ionic field, is considered as static, so that it is averaged considering a known field distribution (see, for example, Hooper 1968;or Iglesias & Lebowitz 1984). The electronic field is considered to be formed as a sequence of non-overlapped individual collisions with a very short length in the typical duration of the emission process.…”

Microfield distributions in strongly coupled two-component plasmas

“…g αR (r) → g αi (r), which reduces Eqs. (40) and (41) for H + and Al 13+ TCPs, respectively. Beyond this value the numerical procedure does either not converge or ends up in unphysical solutions.…”

Effects of Time Ordering on Plasma-Broadened Hydrogen Profiles

“…20 Hooper's static microfield distributions were used in the final-profile calculations. 26 Profiles of H a and H 6 obtained during recent experiments 1 and calculated with and without time ordering are shown in Figs. 1 and 2.…”