An extremely enhanced ionization in the E region of Mars due to high energy electron impact: Comparison of E-peak density observed by MARSIS and ROSE observations

We report an unusual event on 2 June 2012 in the mini-magnetosphere of Mars from Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) onboard Mars Express (MEX) during orbit # 10723 at Ls 119 o , when the E-peak electron density ~ 1.7 x 10 5 cm − 3 enhanced significantly at altitude ~ 100 km. This peak density is higher by about an order of magnitude from the E peak density observed by Radio Occultation Science Experiment (ROSE) onboard Mars Atmospheric and Volatile Evolution (MAVEN). We have modeled observed electron density profiles using coupled continuity and Analytical Yield Spectrum (AYS) approach. In this calculation, we have used solar EUV, X-ray and high-energy electron flux of Electron Spectrometer (ELS)/Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3). The estimated electron density due to solar EUV/X-ray is matching well with the ROSE observation. The enhanced E-peak in the MARSIS profile is produced due to high-energy electron impact.