Temporally resolved light emission and optical emission spectroscopy of surface flashover in vacuum

Raimi Clark, Jacob Young, William Brooks, Matthew Hopkins, John Mankowski, Jacob Stephens, Andreas Neuber

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


Early light emission provides information about the dominant mechanisms culminating in vacuum surface flashover (anode-initiated vs. cathode-initiated) for particular geometries. From experimental evidence gathered elsewhere, for the case of an insulator oriented at 45° with respect to the anode, anode-initiated flashover is believed to dominate since the field at the anode triple point is roughly three times that of the cathode. Similar to previous work performed on cathode-initiated flashover, light emission from the voltage rise through the impedance collapse is collected into two optical fibers focused on light emanating from the insulator in regions near the anode and cathode. The optical fibers are either connected to PMTs for spectrally integrated localized light intensity information or to a spectrograph used in conjunction with an ICCD camera. Challenges associated with localizing the flashover for optical diagnostics and incorporating the optical diagnostics into the high-field environment are discussed. Initial results for cross-linked polystyrene (Rexolite 1422) support the premise that flashover is initiated from the anode for these geometries, as early light from the anode leads cathode light up to photocathode saturation. Early spectroscopy results show promise for future characterization of the spatio-temporal development of emission from desorbed gas species across the insulator surface and identification of bulk insulator involvement if it occurs.

Original languageEnglish
Title of host publication2021 IEEE Pulsed Power Conference, PPC 2021
PublisherInstitute of Electrical and Electronics Engineers Inc.
ISBN (Electronic)9781665433471
StatePublished - 2021
Event2021 IEEE Pulsed Power Conference, PPC 2021 - Denver, United States
Duration: Dec 12 2021Dec 16 2021

Publication series

NameIEEE International Pulsed Power Conference
ISSN (Print)2158-4915
ISSN (Electronic)2158-4923


Conference2021 IEEE Pulsed Power Conference, PPC 2021
Country/TerritoryUnited States


  • anode-initiation
  • light emission
  • optical diagnostics
  • spectroscopy
  • surface flashover


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