Schumann Resonance from Earth to Titan Dana Ionita School of Earth & Atmospheric Sciences Georgia Institute of Technology Outline Definition Earth cavity dimensions & properties Titan (properties) Huygens probe (observations) cavity dimensions & properties (a bit more complex) energy source: ??? possibilities liquid ocean Conclusion: 2 big questions about Titan Schumann waves Resonance waves of the atmospheric cavity formed between the Earth’s surface and ionosphere, two conductive surfaces with a non-conductive atmosphere Simoes et al. (2007) Earth Dimensions & properties Surface conductivity (s) = (land) and 1 (sea) S m-1 Frequencies (obs) = , 14, 20, 26, 33, 39, 45 Hz (+/- Hz daily) Cavity height (h) = 100 km Radius (Rp) = 6378 km Skin depth (d) = 0 km Energy source: lightning Siingh et al. (2006) Titan Cavity properties Ionosphere at 1,200 km, 63 km h (s ~ 10-3 S m-1) = 750 km Surface conductivity (s) = 10-10 S m-1 Radius (Rp) = 2575 km Skin depth (d) = 100 km Simoes et al. (2008) Frequencies on Titan Huygens (Jan 14, 2005) observed: 36 Hz ELF wave Instrumentation noise most likely ruled out as source Model results: (), (), () Hz Beghin et al (2007) Energy source ??? Lightning not observed, but not ruled out Titan ionosphere &
