The Mars aurora: UV detections and in situ electron flux measurements

International audience; A detailed search through the database of theSPICAM instrument on board Mars Express made itpossible to identify 16 signatures of the CO Cameronand CO2 doublet auroral emissions. These auroralUV signatures are all located in the southern hemisphere in the vicinity of the statistical boundary between open and closed field lines. The energy spectrum of the energetic electrons was simultaneously measured by ASPERA-3/ELS at higher altitude. The UV aurora is generally shifted from the region of enhanced downward electron energy flux by a few to several tens of degrees of latitude, suggesting that precipitation occurs in magnetic cusp like structures along inclined magnetic field lines. The ultraviolet brightness shows no proportionality with the electron flux measured at the spacecraft altitude. The Mars aurora appears as a sporadic short-lived feature. Results of Monte Carlo simulations will be compared with the observed brightness of the Cameron and CO2 + bands.