HR: 0800h
AN: P41B-11    [Abstracts]
TI: Conductivity and Electron Density in Titan's Atmosphere as Deduced From Mutual Impedance Measurements by the PWA-HASI Instrument on HUYGENS
AU: * Hamelin, M
EM: michel.hamelin@cetp.ipsl.fr
AF: Centre d'etude des Environments Terrestre et Planétaires (CETP), CNRS, 4 avenue de Neptune, Saint Maur, 94107, France
AU: Béghin, C
EM: cbeghin@cnrs-orleans.fr
AF: Laboratoire de Physique et Chimie de l'Environnement (LPCE), CNRS, 3A Avenue de la Recherche Scientifique, Orléans, 45071, France
AU: Brown, V J
EM: brown@iaa.es
AF: Instituto de Astrofisica de Andalucia (IAA), CSIC, PO box 3004, Granada, 18080, Spain
AU: Grard, R
EM: rgrard@rssd.esa.int
AF: Research and Scientific Support Department (RSSD), ESA/ESTEC, Keplerlaan, Noordwijk, 2200 AG, Netherlands
AU: Jernej, I
EM: Irmgard.Jernej@oeaw.ac.at
AF: Space Research Institute, Austrian Academy of Sciences (IWF), Schmiedlstrasse 6, Graz, 8042, Austria
AU: López-Moreno, J J
EM: lopez@iaa.es
AF: Instituto de Astrofisica de Andalucia (IAA), CSIC, PO box 3004, Granada, 18080, Spain
AU: Schwingenschuh, K
EM: konrad.schwingenschuh@oeaw.ac.at
AF: Space Research Institute, Austrian Academy of Sciences (IWF), Schmiedlstrasse 6, Graz, 8042, Austria
AU: Simões, F
EM: fernando.simoes@cetp.ipsl.fr
AF: Centre d'etude des Environments Terrestre et Planétaires (CETP), CNRS, 4 avenue de Neptune, Saint Maur, 94107, France
AU: Trautner, R
EM: roland.trautner@esa.int
AF: Research and Scientific Support Department (RSSD), ESA/ESTEC, Keplerlaan, Noordwijk, 2200 AG, Netherlands
AU: Molina-Cuberos, G J
EM: gregomc@um.es
AF: Applied Electromagnetic Group, Department of Physics, University of Murcia, Santo Cristo 1, Murcia, 30100, Spain
AU: Berthelier, J
EM: jean-jacques.berthelier@cetp.ipsl.fr
AF: Centre d'etude des Environments Terrestre et Planétaires (CETP), CNRS, 4 avenue de Neptune, Saint Maur, 94107, France
AU: Chabassière, M
EM: michel.chabassiere@cnrs-orleans.fr
AF: Laboratoire de Physique et Chimie de l'Environnement (LPCE), CNRS, 3A Avenue de la Recherche Scientifique, Orléans, 45071, France
AU: Falkner, P
EM: Peter.Falkner@esa.int
AF: Research and Scientific Support Department (RSSD), ESA/ESTEC, Keplerlaan, Noordwijk, 2200 AG, Netherlands
AU: Ferri, F
EM: francesca.ferri@unipd.it
AF: CISAS "G. Colombo", Università di Padova, Via Venezia 15, Padova, 35131, Italy
AU: Fulchignoni, M
EM: marcello.fulchignoni@obspm.fr
AF: LESIA, Observatoire de Paris, 5 place Janssen, Meudon, 92195, France
AU: Jeronimo, J J
EM: jeronimo@iaa.es
AF: Instituto de Astrofisica de Andalucia (IAA), CSIC, PO box 3004, Granada, 18080, Spain
AU: Lara, L M
EM: lara@iaa.es
AF: Instituto de Astrofisica de Andalucia (IAA), CSIC, PO box 3004, Granada, 18080, Spain
AU: Rodrigo, R
EM: rodrigo@iaa.es
AF: Instituto de Astrofisica de Andalucia (IAA), CSIC, PO box 3004, Granada, 18080, Spain
AU: Tokano, T
EM: tokano@geo.Uni-Koeln.de
AF: Institut für Geophysik und Meteorologie, Univ. zu Köln, Albertus-Magnus-Platz, Köln, 50923, Germany
AB: During the descent of the HUYGENS Probe through the atmosphere of Titan, January 14th, 2005, the Permittivity, Waves and Altimetry (PWA), a subsystem of the HUYGENS Atmospheric Structure Instrument (HASI) detected an ionized layer around the altitude of 60 km with two different instruments, the Relaxation Probe (RP) and the Mutual Impedance Probe (MIP). For both instruments a more detailed data analysis, including unforeseen environmental effects, was necessary to reach precise quantitative estimations of the electrical conductivity. The present work is dedicated to the MIP data analysis. New laboratory tests have been performed to correct and validate the calibration data. Temperature effects have been included and two different numerical models of MIP electrodes and circuits in the HUYGENS body have been used. The effect of motion of HUYGENS in the ionized atmosphere that was neglected in the first analysis is revealed and analytical estimations of this effect allow to derive more accurate values of the conductivity profile. The final results are discussed and compared to the RP results. Electron density profiles are deduced showing more precisely the lower ionized layer and its surprisingly steep lower and higher boundaries, not predicted by any model. We conclude that the spatial variability of the free electron density is probably due to aerosol layers that can capture the electrons created in the medium.
DE: 0343 Planetary atmospheres (5210, 5405, 5704)
DE: 2459 Planetary ionospheres (5435, 5729, 6026)
DE: 3304 Atmospheric electricity
DE: 3311 Clouds and aerosols
DE: 6281 Titan
SC: Planetary Sciences [P]
MN: 2007 Joint Assembly