Population inversion in helium in supersonic plasma expansion

Journal Article · Mon May 01 04:00:00 EDT 1978 · Sov. Phys. - Tech. Phys. (Engl. Transl.); (United States)

OSTI ID:6483544

Zhinzhikov, G M; Luk'yanov, G A; Nazarov, V V; Pavlova, N O

The conditions associated with a population inversion of the He I levels with principal quantum numbers 4 and 3 are studied in the supersonic expansion of helium plasma from circular and plane nozzles into a low-pressure region. In an axisymmetric jet the population inversion arises at some finite distance from the nozzle; in plane jets the inversion occurs immediately beyond the slit nozzle. The experimental results are compared with calculations. The experimental data confirm the operation of a recombination mechanism for the population of the He I levels under the experimental conditions and show that a population inversion can be achieved by virtue of the difference in the rates of impact decay of the levels. The population inversion found experimentally corresponds to gain values of the order of 0.1 m/sup -1/. Diffusion of nitrogen from the surrounding medium into the jet reduces the population inversion.

• Research Organization: Leningrad Mechanics Institute
• OSTI ID: 6483544
• Journal Information: Sov. Phys. - Tech. Phys. (Engl. Transl.); (United States), Journal Name: Sov. Phys. - Tech. Phys. (Engl. Transl.); (United States) Vol. 23:5; ISSN SPTPA
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420300* -- Engineering-- Lasers-- (-1989)
ATOM COLLISIONS
COLLISIONS
CRYOGENIC FLUIDS
DIFFUSION
ELEMENTS
FLUID FLOW
FLUIDS
GAS LASERS
HELIUM
LASERS
NITROGEN
NONMETALS
NOZZLES
PLASMA
POPULATION INVERSION
RARE GASES
RECOMBINATION
SUPERSONIC FLOW