On the small-scale fluctuations in the peak electron density of Martian ionosphere observed by MEX/MARSIS

► Peak electron density fluctuation of 6% is observed in Martian ionosphere. ► They are physical and uncorrelated to magnetic anomalies. ► Their power spectra follow the −5/3 power law, implying the existence of turbulence. ► Density fluctuation in the neutral atmosphere is proposed to be the cause. ► This phenomenon may serve as a proxy of the turbulence in upper Martian atmosphere.