Properties of Flapping Current Sheet of the Martian Magnetotail

Abstract

AbstractKnowing the properties of the Martian magnetotail flapping waves is critical to understand the dynamics of the Martian induced magnetosphere. Based on the measurements by Mars Atmosphere and Volatile EvolutioN and a newly developed method, we provide the first quantitative study of Martian magnetotail flapping waves in comparison with Earth's magnetotail flapping waves. We found that the period of Martian magnetotail flapping waves ranges from ∼50 to ∼250 s. The estimated average wave amplitude is ∼380 km, and the wavelength is ∼1,100 km. The estimated propagation speed ranges from ∼3 to ∼30 km/s, which is about a third of that of Earth's magnetotail flapping waves, and the speed declines with the increase of the current sheet thickness. Intriguingly, we found that the flapping waves with shorter periods, or lower wavelengths, can propagate faster, showing similar dispersive signatures as that found in the Earth's magnetotail. Our results demonstrate that the fluctuated field energy carried by flapping waves within unit time along unit magnetotail length is one order higher than that of Earth's flapping waves, as normalized by the magnetic energy of planetary magnetotail. Thus, in comparison with Earth's magnetotail, the flapping waves of Martian induced magnetotail would play a more important role in affecting the magnetotail dynamics.