Concurrent observations of ultraviolet aurora and energetic electron precipitation with Mars Express. Issue 8 (7th August 2015)

• Record Type: Journal Article
• Authors: Gérard, J.‐C.; Soret, L.; Libert, L.; Lundin, R.; Stiepen, A.; Radioti, A.; Bertaux, J.‐L.
• Is Part Of: Journal of geophysical research. Volume 120:Issue 8(2015:Aug.)
• Page Start: 6749
• Page End: 6765
• Publication Date: 2015-08-07
• Subjects: Mars -- aurora -- ultraviolet -- electron -- precipitation; Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/2015JA021150
• Languages: English
• ISSNs: 2169-9380

Abstract

Abstract: The database of the Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars (SPICAM) instrument between late January 2004 and Mars 2014 has been searched to identify signatures of CO Cameron and CO2 + doublet ultraviolet auroral emissions. This study has almost doubled the number of auroral detections based on SPICAM spectra. Auroral emissions are located in the vicinity of the statistical boundary between open and closed field lines. From a total of 113 nightside orbits with SPICAM pointing to the nadir in the region of residual magnetic field, only nine nightside orbits show confirmed auroral signatures, some with multiple detections along the orbital track, leading to a total of 16 detections. The mean energy of the electron energy spectra measured during concurrent Analyzer of Space Plasma and Energetic Atoms/Electron Spectrometer observations ranges from 150 to 280 eV. The ultraviolet aurora may be displaced poleward or equatorward of the region of enhanced downward electron energy flux by several tens of seconds and shows no proportionality with the electron flux at the spacecraft altitude. The absence of further UV auroral detection in regions located along crustal magnetic field structures where occasional aurora has been observed indicates that the Mars aurora is a time‐dependent feature. These results are consistent with the scenario of acceleration of electrons by transient parallel electric field along semiopen magnetic field lines. Key Points: UV aurora and in situ electron precipitation have been simultaneously observed Aurorae are transient events near the open‐closed file line boundary The auroral emission may be shifted from the enhanced electron flux