Waves at the proton cyclotron frequency at Mars

Waves have been measured by Mars Global Surveyor at the local proton cyclotron frequency in the solar wind around Mars [1,2]. We present new analyses of high resolution measurements of Mars Global Surveyor magnetometer and electron spectrometer during the aerobraking hiatus. Comparison with observations by Mars Express SPICAM instrument helps to obtain new insights in the connection between the spatial distribution of these waves and the geometry of the Martian hydrogen exosphere. Implications for the future Maven observations are discussed.