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The energetics of Titan's ionosphereWe have developed a comprehensive model to study the dynamics and energetics of the ionosphere of Titan. We solved the one-dimensional, time-dependent, coupled continuity and momentum equations for several ion species, together with single ion and electron energy equations, in order to calculate density, velocity, and temperature profiles. Calculations were carried out for several cases corresponding to different local times and configurations of the Titan-Saturn system. In our model the effects of horizontal magnetic fields were assumed to be negligible, except for their effect on reducing the electron and ion thermal conductivities and inhibiting vertical transport in the subram region. The ionospheric density peak was found to be at an altitude of about 1100 km, in accordance with earlier model calculations. The ionosphere is chemically controlled below an altitude of about 1500 km. Above this level, ion densities differ significantly from their chemical equilibrium values due to strong upward ion velocities. Heat is deposited in a narrow region around the ionospheric peak, resulting in temperature profiles increasing sharply and reaching nearly constant values of 800-1000 deg K for electrons and 300 deg K for ions in the topside, assuming conditions appropriate for the wake region. In the subram region magnetic correction factors make the electron heat conductivities negligible, resulting in electron temperatures increasing strongly with altitude and reaching values in the order of 5000 deg K at our upper boundary located at 2200 km. Ion chemical heating is found to play an important role in shaping the ion energy balance in Titan's ionosphere.
Document ID
19950037009
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Roboz, A.
(University of Michigan, Ann Arbor, MI United States)
Nagy, A. F.
(University of Michigan, Ann Arbor, MI United States)
Date Acquired
August 16, 2013
Publication Date
February 1, 1994
Publication Information
Publication: Journal of Geophysical Research
Volume: 99
Issue: A2
ISSN: 0148-0227
Subject Category
Lunar And Planetary Exploration
Accession Number
95A68608
Funding Number(s)
CONTRACT_GRANT: NAGW-1619
CONTRACT_GRANT: JPL-959052
Distribution Limits
Public
Copyright
Other

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