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| Titel |
Sprite discharges on Jupiter, Saturn and Venus: Laboratory Experiments in Planetary Gas Mixtures |
| VerfasserIn |
Daria Dubrovin, Sander Nijdam, Eddie van Veldhuizen, Ute Ebert, Yoav Yair, Colin Price |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250047902
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| Zusammenfassung |
| Lightning was optically observed on Jupiter and recently on Saturn. Indirect evidence suggests that some electrical activity occurs on Venus. The charge accumulated within the thunderclouds, and the strong electric fields induced by this charge prior (and after) the flash may initiate sprite-like discharges in the planetary atmosphere above the clouds and below the planetary ionosphere [Yair et al., 2009]. Sprites at mesospheric altitudes on Earth have been found to be physically similar to streamer discharges in air at sea level density. Based on this understanding, we investigated possible sprite discharges in the atmospheres of the gas giant planets and on Venus through laboratory experiments on streamers in appropriate CO2-N2 and H2-He mixtures at variable pressures. Streamer diameters, velocities, radiance and overall morphology were investigated, by means of fast ICCD camera images [Dubrovin et al., 2010]. Scaling laws were confirmed by examining minimal diameters of streamers. The spectrum of the discharges was measured and found to be dominated by the minority species N2 on Venus, and by the radiative dissociation continuum of H2 in the near UV on the gas giants. The spectrum of a fully developed spark was also measured. The spectrum in the hot plasma discharge (equivalent to lightning) is markedly different from the spectrum created by the cold plasma of the streamers.
Yair, Y., Y. Takahashi, R. Yaniv, U. Ebert, and Y. Goto (2009), A study of the possibility of sprites in the atmospheres of other planets, J. Geophys. Res., 114, E09002, doi:10.1029/2008JE003311
Dubrovin, D., S. Nijdam, E. M. van Veldhuizen, U. Ebert, Y. Yair, and C. Price (2010), Sprite discharges on Venus and Jupite-like planets: A laboratory investigation, J. Geophys. Res., 115, A00E34, doi:10.1029/2009JA014851. |
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