Evidence of electrical activity on Titan drawn from the Schumann resonances sent by Huygens probe

Schumann Resonance for Tyros

“…Rabinowicz 1982, 1987;Sentman 1990;Molina-Cuberos et al 2001, 2004Tokano et al 2001;Nickolaenko et al 2003;Pechony and Price 2004;Béghin et al 2007;Navarro et al 2007;Simões et al 2007Simões et al , 2008aMorente et al 2008;Fischer and Gurnett 2011 and references therein). Rabinowicz 1982, 1987;Sentman 1990;Molina-Cuberos et al 2001, 2004Tokano et al 2001;Nickolaenko et al 2003;Pechony and Price 2004;Béghin et al 2007;Navarro et al 2007;Simões et al 2007Simões et al , 2008aMorente et al 2008;Fischer and Gurnett 2011 and references therein).…”

Comment on “An analysis of VLF electric field spectra measured in Titan's atmosphere by the Huygens probe” by J. A. Morente et al.

“…Morente and his coworkers have revisited this data set and reported the results of their investigations in two papers. In a first paper, they claim that they have detected in the ELF range (0–100 Hz) several harmonics of a global resonance allegedly generated by lightning activity in the spherical cavity guide formed by the surface of Titan and the inner boundary of the ionosphere, a phenomenon similar to the Schumann resonance observed at Earth [ Morente et al , 2008]. In the second paper dedicated to the VLF electric signal recorded by PWA, in the range 0–10 kHz, they argue that they can also bring out the transverse resonance and its harmonics, a more local phenomenon that develops around the excitation source and whose frequency is controlled by the separation between Titan's surface and the inner ionospheric boundary [ Morente et al , 2009b].…”

“…The PWA investigators have analyzed the narrow‐band ELF signal at about 36 Hz effectively observed during the entire descent [ Grard et al , 2006; Béghin et al , 2007; Simões et al , 2007] and are still scrutinizing its significance [ Béghin et al , 2009]. They have not endorsed, however, the alternative approach of Morente et al [2008] that discloses additional ELF narrow‐band signals and numerous related harmonics. Hamelin et al [2009] and Béghin et al [2009] have questioned the work of Morente and his coworkers and demonstrated unambiguously that their findings are mere artifacts entirely due to a faulty procedure.…”

“…The analyses of the ELF and VLF signals by Morente and his coworkers are flawed, and their conclusions are shown here to be invalid. A more comprehensive and thorough assessment of the numerical approaches proposed by Morente et al [2008, 2009b] is given by Berthelin et al [2009].…”

Phosphorus chemistry on Titan

“…In the presence of a reducing atmosphere, reduction would take place even more readily (Glindemann et al, 1999). Lightning has not been detected on Titan (Fischer et al, 2007;Morente et al, 2008), and convective storms potentially capable of generating lightning will be much less abundant on Titan than on the Earth due to the lower solar flux at the former (Awal and Lunine, 1994).…”