Spectroscopic measurements of streamer filaments in electric breakdown in a dielectric liquid

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Emission spectroscopy has been utilized to provide information about the electron density and temperature in streamers and breakdown arcs in transformer oil. Recorded spectra include strongly broadened hydrogen Balmer-alpha lines and vibration/rotation band profiles of the C-2 molecule. The origin of the observed broadening of hydrogen lines is discussed and it is concluded that it arises mainly from collisions with charged particles, so-called dynamic Stark broadening. By assuming that the broadening is due solely to dynamic Stark broadening, electron densities between 1 x 10(18) and 1 x 10(19) cm(-3) were obtained for the rear of positive streamer filaments during the later stages of propagation. For negative streamers we obtained an upper limit of 3 x 10(16) cm(-3) and for breakdown arcs electron densities up to 4 x 10(18) cm(-3). The temperature information in the C-2 emission profiles and the intensity ratio of the hydrogen Balmer lines are discussed. Rough estimations of the temperature are presented both for positive and for negative streamers.


Enheter & grupper

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Atom- och molekylfysik och optik
Sidor (från-till)1188-1196
TidskriftJournal of Physics D: Applied Physics
Utgåva nummer5
StatusPublished - 1996
Peer review utfördJa


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