Positive streamers in air of varying density: experiments on the scaling of the excitation density
| Autor: | Colin Price, Yoav Yair, Ttj Clevis, D. Dubrovin, Ute Ebert, S Sander Nijdam, Lcj Luuk Heijmans |
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| Přispěvatelé: | Elementary Processes in Gas Discharges, Extreme non-equilibrium plasmas, Multiscale Dynamics |
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Electron density
radiance Photon Acoustics and Ultrasonics Chemistry Electron Condensed Matter Physics Surfaces Coatings and Films Electronic Optical and Magnetic Materials sprites Electric field Ionization Excited state excitation density Atomic physics electron density Scaling Excitation streamers |
| Zdroj: | Journal of Physics D: Applied Physics, 48(5), 055205-1/10. Institute of Physics Journal of Physics D: Applied Physics, 48, 1-10 |
| ISSN: | 0022-3727 |
| Popis: | Streamers are rapidly extending ionized finger-like structures that dominate the initial breakdown of large gas volumes in the presence of a sufficiently strong electric field. Their macroscopic parameters are described by simple scaling relations, where the densities of electrons and of excited molecules in the active streamer front scale as the square of the density of the neutral gas. In this work we estimate the absolute density of nitrogen molecules, excited to the C3Πu state that emit photons in the 2P–N2 band, by radiometrically calibrated short exposure intensified imaging. We test several pressures (100, 200 and 400 mbar) in artificial air at room temperature. Our results provide a first confirmation for the scaling of the density of excited species with the gas density. The method proposed here is particularly suitable to characterize the excitation densities in sprite streamers in the atmosphere. |
| Databáze: | OpenAIRE |
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