Observations of Photoelectron Energy Peaks Below 400 km in the Dayside Ionosphere of Mars
Abstract
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).
- Publication:
-
AGU Spring Meeting Abstracts
- Pub Date:
- May 2007
- Bibcode:
- 2007AGUSMSM23B..07F
- Keywords:
-
- 2431 Ionosphere/magnetosphere interactions (2736);
- 2459 Planetary ionospheres (5435;
- 5729;
- 6026);
- 5435 Ionospheres (2459);
- 5440 Magnetic fields and magnetism;
- 6225 Mars