How are particles being energized by turbulent electromagnetic fields is an outstanding question in plasma physics and astrophysics. This paper investigates the electron acceleration mechanism in strong turbulence (δB/B0 ~ 1) in the Earth’s magnetosheath based on the novel observations of the Magnetospheric Multiscale (MMS) mission. We find that electrons are magnetized in turbulent fields for the majority of the time. By directly calculating the electron acceleration rate from Fermi, betatron mechanism, and parallel electric field, it is found that electrons are primarily accelerated by the parallel electric field within coherent structures. Moreover, the acceleration rate by parallel electric fields increases as the spatial scale reduces, with the most intense acceleration occurring over about one ion inertial length. This study is an important step towards fully understanding the turbulent energy dissipation in weakly collisional plasmas.

As there are strong crustal magnetic fields in some Martian concentrated regions. it has long been a goal of Martian science to understand how crustal magnetic field affects surrounding space environment. In the paper, using the data measured by MAVEN, the ratio of electron/CO2 density ( Ne/NCO2) in region with different levels of Martian ionospheric magnetic fields are studied. It seems that ratio of dayside Ne/NCO2 in region with stronger ionospheric magnetic field is larger while the altitude is more than 260 km. On the other hand, the effect of crustal magnetic field intensity on the nightside ratio of Ne/NCO2 is weak. Since the topological structure of magnetic field is very vulnerable to the solar wind, the correlation between Ne/NCO2 and solar wind parameters are analyzed. We find that there is obvious negative correlation between dayside ratio of Ne/NCO2 and solar wind dynamic pressure in the region with strong ionospheric magnetic field, which may imply that the ionospheric plasmas are significantly escaped in response to enhanced solar wind dynamic pressure pulses in the dayside region. However, the effect of solar wind on nightside ratio of Ne/NCO2 is very little. These results can be useful for understanding the dynamic process in the Martian ionosphere.