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.