TY - JOUR IS - 21 N1 - Copyright 2006 by the American Geophysical Union VL - 33 AV - public Y1 - 2006/11/01/ TI - Electron temperature of Titan's sunlit ionosphere A1 - Galand, M A1 - Yelle, RV A1 - Coates, AJ A1 - Backes, H A1 - Wahlund, JE KW - Photoionization cross-sections KW - Upper-atmosphere KW - Plasma KW - Photoelectron KW - Model KW - Rates JF - Geophysical Research Letters UR - http://dx.doi.org/10.1029/2006GL027488 PB - AMER GEOPHYSICAL UNION SN - 0094-8276 N2 - Titan's upper atmosphere is ionized by solar radiation and particle bombardment from Saturn's magnetosphere. The induced ionosphere plays a key role in the coupling of Titan's atmosphere with the Kronian environment. It also provides unique signatures for identifying energy sources upon Titan's upper atmosphere. Here we focus on observations from the first, close flyby by the Cassini spacecraft and assess the ionization and electron heating sources in Titan's sunlit ionosphere. We compare CAPS electron spectra with spectra produced by an electron transport model based on the INMS neutral densities and a MHD interaction model. In addition, we compare RPWS electron temperature against the models. The important terms in the electron energy equation include loss through excitation of vibrational states of N-2 and CH4, Coulomb collisions with suprathermal electrons, and thermal conduction. Our analysis highlights the important role of the magnetic field line configuration for aeronomic studies at Titan. ID - discovery113947 ER -