Population distributions in Li vapor excited by a photoionization electron source
Abstract
A detailed theoretical and experimental investigation is presented of the excited-level population distribution in a Li-Ne vapor under excitation by a photoionization electron source. This source produces a subnanosecond burst of hot (Te~20 eV) electrons with a peak density in excess of 5×1015 cm-3. The electrons are generated as a result of photoionization of Ne atoms by x rays emitted from a plasma produced by a 100-mJ laser pulse of 600 ps duration. Measurements of Li(1s22p)-atom density, and of electron density, have been performed with subnanosecond time resolution under various conditions of excitation. A comprehensive rate-equation model is described and its predictions are seen to be in good agreement with experiment. It is shown that the population distribution in the Li-Ne vapor is strongly influenced by recombination. Under the conditions of these experiments, rates for this process as high as 3×109 s-1 were observed.
- Publication:
-
Physical Review A
- Pub Date:
- April 1986
- DOI:
- 10.1103/PhysRevA.33.2563
- Bibcode:
- 1986PhRvA..33.2563C
- Keywords:
-
- Atomic Energy Levels;
- Electron Sources;
- Laser Plasmas;
- Lithium;
- Metallic Plasmas;
- Photoionization;
- Atom Concentration;
- Electron Density (Concentration);
- Metal Vapors;
- Neon;
- Pulsed Lasers;
- Plasma Physics;
- 32.80.Fb;
- 34.80.Dp;
- 52.50.Jm;
- Photoionization of atoms and ions;
- Atomic excitation and ionization by electron impact;
- Plasma production and heating by laser beams