HR: 1340h
AN: P53A-1452    [Abstracts]
TI: Predictions of the Electrical Conductivity and Charging of the Aerosols in Titan's Atmosphere
AU: * Whitten, R C
EM: rwhitten@pacbell.net
AF: SETI Institute, 515 N. Whisman Road, Mountain View, CA 94043 United States
AU: Borucki, W J
EM: wjborucki@comcast.net
AF: NASA-Ames Research Center, Moffett Federal Airfield, Moffett Field, CA 94035
AU: Bakes, E L
EM: wandstar2004@yahoo.com
AF: SETI Institute, 515 N. Whisman Road, Mountain View, CA 94043 United States
AU: Barth, E
EM: ebarth@boulder.swri.edu
AF: Southwest Research Institute, 1050 Walnut Street, Suite 400 , Boulder, CO 80302 United States
AU: Tripathi, S
AF: Indian Institute of Technology, Indian Institute of Technology, Kanpur, 208016 India
AB: The electrical conductivity and electrical charge on the aerosols in the atmosphere of Titan will be presented for altitudes between 0 and 400 km as well as for both daytime and nighttime conditions. Ionization due to both galactic cosmic rays and electron precipitation from Saturn's magnetosphere is included. This ionization results in the production of free electrons and the primary ions N2+ and N+ which are then rapidly converted into secondary ions such as H2CN+ and NH4+ which in turn form ion clusters such as H2CN+ (HCN)n. and NH4+(NH3)m. Because polycyclic aromatic hydrocarbons (PAHs) have been observed in the laboratory and found to be electrophillic, we also include the formation of negative ions. The ubiquitous aerosols observed in the Titan atmosphere play an important role in determining the charge distribution in the atmosphere acting as a store for negative charge on the night side by attaching electrons. This is particularly the case if large concentrations of negative ion-forming particles are present. On the day side, on the other hand, solar UV causes the aerosols to copiously emit electrons because of the low ionization potential of graphitic material even when the effect of the finite size of the particles (the Coulomb term) is included. The prediction of large electron densities on the day side as a result of photo emission of electrons by the aerosol particles is amenable to checking by the radio occultation method. Charge distributions on the aerosol particles have been computed and will be presented; they predict the accumulation of large electric charge on the 0.2 micron particles, peaking at about 400 charges at some altitudes. We will also present the computed electrical conductivities, which can be measured by the Huygens probe.
DE: 5409 Atmospheres--structure and dynamics
DE: 6280 Saturnian satellites
DE: 0305 Aerosols and particles (0345, 4801)
SC: Planetary Sciences [P]
MN: 2004 AGU Fall Meeting