Probing photo-ionization: simulations of positive streamers in varying N2 : O2-mixtures
By G. Wormeester, Sergey Pancheshnyi, Alejandro Luque, S. Nijdam, Ute Ebert. 2010
158 citations recorded by the source corpus.
Photo-ionization is the accepted mechanism for the propagation of positive streamers in air though the parameters are not very well known; the efficiency of this mechanism largely depends on the presence of both nitrogen and oxygen. But experiments show that streamer propagation is amazingly robust against changes of the gas composition; even for pure nitrogen with impurity levels below 1 ppm streamers propagate essentially with the same velocity as in air, but their minimal diameter is smaller, and they branch more frequently. Additionally, they move more in a zigzag fashion and sometimes exhibit a feathery structure. In our simulations, we test the relative importance of photo-ionization and of the background ionization from pulsed repetitive discharges, in air as well as in nitrogen with 1 ppm O2. We also test reasonable parameter changes of the photo-ionization model. We find that photo-ionization dominates streamer propagation in air for repetition frequencies of at least 1 kHz, while in nitrogen with 1 ppm O2 the effect of the repetition frequency has to be included above 1 Hz. Finally, we explain the feather-like structures around streamer channels that are observed in experiments in high purity nitrogen, but not in air.
Subfields: Electrical and Electronic Engineering, Radiology, Nuclear Medicine and Imaging, Spectroscopy
View Paper: https://www.semanticscholar.org/paper/04f4130ca8e1ce1df416c5684467619828143463
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In Electrical and Electronic Engineering
In Radiology, Nuclear Medicine and Imaging
Citations in the corpus
- Dynamics of a guided streamer (‘plasma bullet’) in a helium jet in air at atmospheric pressure (2013, background): “This field strength is much smaller than the maximum field of a streamer in air, which is on the order of 150 kV cm−1 at atmospheric pressure (Babaeva and Naidis 1996, Naidis 2009, Wormeester et al 2010).”