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Title: Time evolution of nanosecond runaway discharges in air and helium at atmospheric pressure

Journal Article · · Physics of Plasmas
DOI:https://doi.org/10.1063/1.4772774· OSTI ID:22072669
; ;  [1]
  1. Physics Department, Technion, Haifa 32000 (Israel)

Time- and space-resolved fast framing photography was employed to study the discharge initiated by runaway electrons in air and He gas at atmospheric pressure. Whereas in the both cases, the discharge occurs in a nanosecond time scale and its front propagates with a similar velocity along the cathode-anode gap, the later stages of the discharge differ significantly. In air, the main discharge channels develop and remain in the locations with the strongest field enhancement. In He gas, the first, diode 'gap bridging' stage, is similar to that obtained in air; however, the development of the discharge that follows is dictated by an explosive electron emission from micro-protrusions on the edge of the cathode. These results allow us to draw conclusions regarding the different conductivity of the plasma produced in He and air discharges.

OSTI ID:
22072669
Journal Information:
Physics of Plasmas, Vol. 19, Issue 12; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
Country of Publication:
United States
Language:
English