Time- and space-resolved light emission and spectroscopic research of the flashover plasma

The results of an experimental study of the evolution of surface flashover across the surface of an insulator in vacuum subject to a high-voltage pulse and the parameters of the flashover plasma are reported. For the system studied, flashover is always initiated at the cathode triple junctions. Using time-resolved framing photography of the plasma light emission the velocity of the light emission propagation along the surface of the insulator was found to be ∼2.5·108 cm/s. Spectroscopic measurements show that the flashover is characterized by a plasma density of 2–4 × 1014 cm−3 and neutral and electron temperatures of 2–4 eV and 1–3 eV, respectively, corresponding to a plasma conductivity of ∼0.2 Ω−1 cm−1 and a discharge current density of up to ∼10 kA/cm2.

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