Shumann resonances and electromagnetic transparence in the atmosphere of Titan
| Autor: | Herbert Lichtenegger, Juan A. Morente, Bruno P. Besser, Hans Eichelberger, Jorge A. Portí, J. Margineda, Gregorio J. Molina-Cuberos, Konrad Schwingenschuh, Alfonso Salinas |
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| Rok vydání: | 2004 |
| Předmět: |
Physics
Atmospheric Science Schumann resonances Waves in plasmas Aerospace Engineering Resonance Astronomy and Astrophysics Atmospheric sciences Electromagnetic radiation Computational physics Troposphere symbols.namesake Geophysics Space and Planetary Science Electric field Physics::Space Physics symbols General Earth and Planetary Sciences Astrophysics::Earth and Planetary Astrophysics Atmosphere of Titan Titan (rocket family) Physics::Atmospheric and Oceanic Physics |
| Zdroj: | Advances in Space Research. 33:2309-2313 |
| ISSN: | 0273-1177 |
| DOI: | 10.1016/s0273-1177(03)00465-4 |
| Popis: | Among the multiple questions that the CASSINI/HUYGENS mission tries to answer is the likelihood of electric discharges in Titan's atmosphere. The instruments “Huygens Atmospheric Structure Instrument” and “Radio and Plasma Wave Science” will probe the electromagnetic emissions during the Huygens descent and Cassini flybys, respectively. Although no lightning was observed during Voyager's encounters with Titan in 1980 and 1981, this does not exclude the existence of lightning phenomena. Recent investigations show that lightning discharges could occur in the lower atmosphere, such as the detection of methane condensation clouds in the troposphere and the theoretical prediction of an electric field that would be sufficient enough to cause lightning. We present a numerical model of Titan's atmosphere with the aim of calculating the resonance frequencies and the atmospheric transparency to electromagnetic waves. The detection and measurement of these resonances, Schumann frequencies, by the Huygens probe, would show the existence of electric activity connected with lightning discharges in the atmosphere. As it happens with the Schumann frequencies of Earth, losses associated with the electric conductivity will make these frequencies to be lower than the theoretically predicted, the fundamental one being located between 11 and 15 Hz. An analytical study shows that the strong losses associated with the high conductivity make it impossible that an electromagnetic wave generated near the surface with a frequency of 10 MHz or lower reaches the outer part of Titan's atmosphere. Therefore the detection of electromagnetic waves coming from Titan's lower atmosphere by the RPWS instrument is very unlikely. |
| Databáze: | OpenAIRE |
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