Author/Authors :
Simُes، نويسنده , , F. and Grard، نويسنده , , R. and Hamelin، نويسنده , , M. and Lَpez-Moreno، نويسنده , , J.J. and Schwingenschuh، نويسنده , , K. and Béghin، نويسنده , , C. and Berthelier، نويسنده , , J.-J. and Besser، نويسنده , , B. and Brown، نويسنده , , V.J.G. and Chabassière، نويسنده , , M. and Falkner، نويسنده , , P. H. Ferri، نويسنده , , F. and Fulchignoni، نويسنده , , M. and Hofe، نويسنده , , R. and Jernej، نويسنده , , I. ، نويسنده ,
Abstract :
The propagation of extremely low frequency (ELF) electromagnetic waves in the Earthʹs ionospheric cavity and the associated resonance phenomena have been extensively studied, in relation with lightning activity. We perform a similar investigation for Titan, the largest moon of Saturn. There are important differences between Earth and Titan, as far as the cavity geometry, the atmospheric electron density profile, and the surface conductivity are concerned. We present an improved 3D finite element model that provides an estimate of the lowest eigenfrequencies, associated quality factors (Q-factors), and ELF electric field spectra. The data collected by the electric antenna of the Permittivity, Waves, and Altimetry (PWA) instrument reveals the existence of a narrow-band signal at about 36 Hz during the entire descent of Huygens upon Titan. We assess the significance of these measurements against the model predictions, with due consideration to the experimental uncertainties.
Keywords :
Huygens probe , ELF electric field , Schumann resonance , Titan , Atmospheric electricity
