Measurement of the Electronic and Ionic Conductivities With a Relaxation Probe in the Atmosphere of Titan

The Permittivity, Waves, and Altimetry (PWA) analyzer, a subsystem of the Huygens Atmospheric Structure Instrument (HASI), landed on Titan in January 2005. This instrument included two Relaxation Probes to measure the electric conductivities of the atmosphere from an altitude of 150km, downwards. We first present a detailed modelisation of the electric system formed by the Huygens Probe body and the relaxation probes. The performance of the instrument is drastically different in the atmosphere of Titan and of the Earth, because the charge carriers are positive and negative ions on Earth, whereas electrons are also present in the case of Titan. Then, we give an interpretation of the experimental data in the light of the simulation results.