Positive streamers in air and other oxygen-nitrogen mixtures are generally believed to propagate against the electron drift direction due to photo-ionization. Photo-ionization is the non-local ionization of O2-molecules by UV radiation from excited N2-molecules. This facilitates the streamer propagation by creating free electrons ahead of it. The relative importance of photo-ionization depends on the O2/N2 ratio. Another possible source of free electrons in front of the positive streamer is background ionization. This can be ionization left by previous discharges or by other processes such as cosmic rays or (natural) radio-activity. We study the effects of both photo- and background-ionization on propagation and morphology of positive streamers by changing gas composition and repetition frequency. One particular gas composition is pure nitrogen with a small amount of radio-active 85Kr added to increase background ionization.
|Title of host publication||Proceedings of the 30th International Conference on Phenomena in Ionized Gases (ICPIG 2011), August 28th- September 2nd, 2011, Belfast, UK|
|Publication status||Published - 2011|
|Event||30th International Conference on Phenomena in Ionized Gases (ICPIG 2011), August 28 - September 2, 2011, Belfast, UK - Belfast, United Kingdom|
Duration: 28 Aug 2011 → 2 Sep 2011
|Conference||30th International Conference on Phenomena in Ionized Gases (ICPIG 2011), August 28 - September 2, 2011, Belfast, UK|
|Abbreviated title||ICPIG 2011|
|Period||28/08/11 → 2/09/11|