Low-temperature supercooled quasi-steady-state beam plasma
Abstract
Formation conditions for a highly supercooled quasi-steady-state plasma produced by an intense electron beam in a dense gas are investigated theoretically and experimentally. The primary means for reducing the electron temperature of the experimental helium plasma involved additions of molecular hydrogen; the electron temperature was decreased by a factor of 2 or 3 in comparison with previously attained values of 0.3 to 0.4 eV by optimizing the experimental conditions. Experimental results are presented which show that under the optimized conditions the electron temperature of a helium-hydrogen mixture with a density of (2 to 8) by 10 to the 18th power per cu cm was no more than about 0.2 eV and the electron density was of the order of 10 to the 14th power per cu cm. It is noted that a plasma with such parameters is extremely nonequilibrium, that the reported plasma density is some 20 orders of magnitude higher than the LTE value defined by the Saha formula, and that the corresponding excess in the density of excited helium atoms is even larger.
- Publication:
-
Zhurnal Eksperimentalnoi i Teoreticheskoi Fiziki
- Pub Date:
- September 1977
- Bibcode:
- 1977ZhETF..73..913S
- Keywords:
-
- Cold Plasmas;
- Dense Plasmas;
- Electron Beams;
- Helium Plasma;
- Plasma-Particle Interactions;
- Supercooling;
- Electron Density (Concentration);
- Electron Energy;
- Plasma Diagnostics;
- Plasma Physics