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On the Likelihood of Electrical Activity in Titan's Tropospheric Clouds

R. Navarro-González (National University of Mexico)

An opportunity to search for lightning in Titan occurred during the Voyager 1 encounter with Saturn. Optically thick cloud and haze layers in the stratosphere prevented lightning detection at optical wavelengths. A search for lightning-radiated signals at radio wavelengths yielded negative results. The lack of terrestrial-like lightning does not dismiss, however, the possibility of other types of unusual lightning discharges in Titan. Titan's atmosphere appears to contain no polarizable gas that could lead to generation of a gross electrical structure of clouds by precipitation mechanisms. Instead the electrical dipole within Titan's clouds could result by convective motions to bring externally derived ions into the cloud, where they are attached to cloud particles. These ions and precipitating particles are continuously being generated by cosmic ray and Saturnian magnetospheric interactions with Titan's atmosphere. The net dipole within the cloud would result from updrafts transporting the positively charged particles to its upper portions while the downdrafts deliver negative charged aerosols from above the cloud top to the base. It is expected that weak electric fields would be developed within Titan's clouds that would result in corona discharge and weak intracloud lightning activity.