Neutral particle density transients in gaseous discharges

1985 ◽  
Vol 28 (2) ◽  
pp. 571
Author(s):  
A. Metze ◽  
D. W. Ernie ◽  
H. J. Oskam ◽  
L. M. Chanin
Keyword(s):  
Neutral Particle ◽  
Particle Density

Influence of Atom-Atom Collisions on the Population Densities of Excited Atomic Levels

1970 ◽  
Vol 25 (1) ◽  
pp. 145-147 ◽  
Author(s):  
H. W. Drawin
Keyword(s):  
Thermal Plasma ◽  
Neutral Particle ◽  
Particle Density ◽  
Coupled System ◽  
Rate Equations ◽  
Gas Temperature ◽  
Hydrogen Atoms ◽  
Population Densities ◽  
Non Thermal Plasma ◽  
Quantitative Spectroscopy

Abstract The number densities of excited hydrogen atoms in a non-thermal plasma have been calculated on the basis of a coupled system of rate equations (25 levels) in which one accounts for electron-atom and atom-atom collisions. The calculated population densities depend strongly on the neutral particle density na when ne/na≪1. When the electron temperature, Te, is different from the gas temperature, Tg , the number densities of the excited levels are determined by Tg rather than by Te. This is important in connection with the quantitative spectroscopy of plasmas.

scholarly journals Ionospheric Irregularities and High-multiple Reflections

1964 ◽  
Vol 17 (4) ◽  
pp. 480 ◽  
Author(s):  
GG Bowman
Keyword(s):  
Acoustic Waves ◽  
Neutral Particle ◽  
Particle Density ◽  
Sunspot Cycle ◽  
Diurnal Variations ◽  
Ionospheric Irregularities ◽  
Upper Atmosphere ◽  
Multiple Reflections ◽  
Annual Variations ◽  
Reflec Tions

The occurrence of high� multiple reflections (10 hops and more) from the F. layer of the ionosphere at night is considered. Sunspot-cycle, annual, and diurnal variations are presented. The sunspot. cycle and annual variations are similar to those for the upper-atmosphere neutral particle density. Periodicities in occurrence of around 60 min are found. Associations are found between high-multiple trace occurrence and sunset and sunrise times at the 90 km level. Ionospheric irregularities which are present at the time of high.multiple reflections indicate that these reflec� tions are probably not due to focusing effects. Evidence is presented to support a mechanism involving the reduction of non�deviative absorption to explain these reflections. This reduction may be caused by acoustic waves propagating in the high atmosphere.

Measurement of the Neutral Particle Density in an Electron Cyclotron Resonance Plasma by Rayleigh Scattering

1995 ◽  
Vol 34 (Part 2, No. 10B) ◽  
pp. L1402-L1404 ◽  
Author(s):  
Wolfgang Cronrath ◽  
Hiroyuki Tanaka ◽  
Mark D. Bowden ◽  
Kiichiro Uchino ◽  
Katsunori Muraoka
Keyword(s):  
Cyclotron Resonance ◽  
Rayleigh Scattering ◽  
Neutral Particle ◽  
Electron Cyclotron Resonance ◽  
Particle Density ◽  
Electron Cyclotron ◽  
Electron Cyclotron Resonance Plasma ◽  
Resonance Plasma

scholarly journals Source Properties of a Hollow Cathode Arc Plasma

1986 ◽  
Vol 41 (4) ◽  
pp. 585-600
Author(s):  
J. M. M. J. Vogels ◽  
L. U. E. Konings ◽  
D. C. Schram
Keyword(s):  
Hollow Cathode ◽  
Neutral Particle ◽  
Particle Density ◽  
Ion Source ◽  
Momentum Balance ◽  
Particle Drift ◽  
Large Velocity ◽  
Arc Current ◽  
Cathode Arc ◽  
Gas Supply

Experiments have been carried out on the properties of a hollow cathode as an ion-source.The measured electron density, ion and neutral temperatures and drift velocities have been compared with predictions from the conservation laws for matter, momentum and energy.Very large exit drift velocities of ions and neutrals are observed. The magnitude and direction, against the electric field, can be explained on the basis of the momentum balance. At weak magnetic field strengths even supersonic drift velocities are found. The charge flux carried by the ions is about five percent of the net arc current. For small flows, the ionized fraction of the gas supply approaches 100%.The neutral particle density outside the cathode consist of a fraction drifting with a large velocity out of the cathode and a fraction of cool background atoms. The change of the ratio of these fractions with increasing distance to the cathode causes the average neutral particle drift to decrease very rapidly.Finally, an analysis of the overall cathode power balance is given.

Sign in / Sign up

Export Citation Format

Share Document