Abstract

A variable-pressure 27-MHz helium plasma was investigated in order to study the physical chemical nature of the inductive coupling and the microscopic atomic and molecular state variations which attend regular manipulations of plasma power and of helium pressure. Two modes of helium plasma excitation, the E- and H-plasma modes, are identified by widely differing capacities to effect ionization of other plasma species such as argon atoms. The switch from the helium E- to the H-plasma is abrupt and dependent on the gas pressure. The results presented suggest that it is the production of He⁺ and electrons and subsequent interactions in the plasma (electron recombination, collisions, etc.) which primarily determine the microscopic atomic and molecular behavior which we observe.

Temporal evolution of laser-induced ionization and recombination processes in argon-helium mixture

Shu Hu, Ke Huang, Feng Zhu, Baodong Gai, Juntao Li, Yannan Tan, and Jingwei Guo
Opt. Continuum 2(12) 2516-2528 (2023)

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Vacuum Ultraviolet Emission from High Density Spark Discharges in Argon and Helium

Lothar Michel and Heinz Fischer
Appl. Opt. 11(4) 899-906 (1972)