HR: 1400h
AN: SM23B-07    [Abstracts]
TI: Observations of Photoelectron Energy Peaks Below 400 km in the Dayside Ionosphere of Mars
AU: Frahm, R A
EM: rfrahm@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228, United States
AU: * Winningham, J
EM: dwinningham@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228, United States
AU: Sharber, J R
EM: jsharber@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228, United States
AU: Jeffers, S J
EM: sjeffers@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78228, United States
AU: Coates, A J
EM: ajc@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University Colledge London, Holmbury St Mary, Dorking, Surry, RH5 6NT, United Kingdom
AU: Linder, D R
EM: drl@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University Colledge London, Holmbury St Mary, Dorking, Surry, RH5 6NT, United Kingdom
AU: Team, A
EM: stas@irf.se
AF: Swedish Institute of Space Physics, Box 812, Kiruna, S-981, Sweden
AB: The Mars Express Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) experiment determines the electron, ion, and neutral particle components of plasma using four instruments: Electron Spectrometer (ELS), Ion Mass Analyzer (IMA), Neutral Particle Imager (NPI), and Neutral Particle Detector (NPD). The ELS instrument determines the electron energy spectrum by collecting 128 logarithmically spaced samples of the electron spectrum between 1 eV and 20 keV every four seconds. When the ASPERA-3 makes measurements within the dayside Martian ionosphere, it detects electrons from the 30.4 nm photoionization peaks of carbon dioxide and atomic oxygen. These photoelectron peaks are typically observed in all ELS directional sectors when they are detected. Thus, spectrograms in the ionosphere have been examined for one ELS sector in a pilot study to determine if and where the electron photoelectron peaks are observed with respect to the planet surface. The locations of these peaks are compared to the map of the radial component of the crustal magnetic fields to determine if the crustal magnetic fields influence the locations of photoelectrons. The comparison is restricted to the region below an altitude of 400 km and bounded at low altitudes by the spacecraft periapsis (250-300 km).
DE: 2431 Ionosphere/magnetosphere interactions (2736)
DE: 2459 Planetary ionospheres (5435, 5729, 6026)
DE: 5435 Ionospheres (2459)
DE: 5440 Magnetic fields and magnetism
DE: 6225 Mars
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Joint Assembly