HR: 0830h
AN: SA41A-01    [Abstracts]
TI: ASPERA-3 ELS Measurements of Photoelectrons from Carbon Dioxide at Mars
AU: * Frahm, R A
EM: rfrahm@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238 United States
AU: Winningham, J
EM: dwinningham@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238 United States
AU: Sharber, J R
EM: jsharber@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238 United States
AU: Persson, K
EM: kpersson@swri.edu
AF: Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238 United States
AU: Linder, D R
EM: drl@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University College London Holmbury St. Mary, Dorking, Surry, RH5 6NT United Kingdom
AU: Coates, A J
EM: ajc@mssl.ucl.ac.uk
AF: Mullard Space Science Laboratory, University College London Holmbury St. Mary, Dorking, Surry, RH5 6NT United Kingdom
AU: Link, R
EM: richard.link@cox.net
AF: Algoma Research, Inc., P.O. Box 7423, Fairfax Station, VA 22039-7423 United States
AU: Team, A
EM: stas@irf.se
AF: Swedish Institute of Space Physics, Box 812, Kiruna, 981 28 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. Its 8% energy resolution is used to resolve the carbon dioxide photoelectron peaks (generated from He 30.4 nm photons) which are a dominant feature in the Martian Ionosphere. However at times, ELS oversamples the electron spectrum by conducting measurements with separation energies smaller than an 8% difference. This oversampling technique is used to improve the ELS measurement of the Mars photoelectron spectrum. During times of oversampling, ELS may be stepped in a linear fashion from 1 eV to 127 eV. In order to recover the photoelectron spectrum oversampling cases, detailed knowledge of the instrument response function must be used along with inversion methods. The procedure increases the energy resolution in the oversampled region of the energy spectrum, and thus, improves the measurement of the amplitudes of the carbon dioxide peaks.
DE: 2423 Ionization mechanisms
DE: 2427 Ionosphere/atmosphere interactions (0335)
DE: 2494 Instruments and techniques
DE: 5435 Ionospheres (2459)
DE: 5464 Remote sensing
SC: SPA-Aeronomy [SA]
MN: 2005 Joint Assembly