Springer Online Journal Archives 1860-2000
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Abstract Particle densities are determined for a decaying axially blown SF6 are between current zero and brekdown, some 100 μs later. During the time of interest, primarily only atoms, diatomic molecules and ions can be built up by reactions. Therefore, in a first approach equilibrium densities are derived for SF6 which has decomposed into its considemic and diatomic components. In a second approach reaction kinetics are considered. It turns out that the development of densities occurs in two steps. During the first approx. 100 μs there is a strong deviation from equilibrium. Afterwards the most abundant particles remain near their partial, diatomic equilibrium values. Near breakdown the degree of ionization is of the order of 1013 cm−3 with the most abundant ions S 2 + and F−. This density is sufficient to distort the applied electric field. Future theories of breakdown in hot gases must take into account this principal difference as compared with the conditions in cold gases.
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