Fundamental Understanding of Magnetic Reconnection via Spiral CT Scan. IX. Statistics of Ion Velocity and Electron Velocity
Year: 2026
Type: article
Abstract: For the first time, we identify the characteristic velocity pattern for ions and electrons in all the regions around two-dimensional (2D) X-line by operating a statistical survey of 16 reconnection events based on the spiral CT scan technique. These reconnection events were detected by the MMS mission at Earth’s magnetopause and have been identified as EDR encounters. According to the statistics, we find the electron velocities have distinct features from ion velocities: (1) electron velocities are directed toward X-point in the inflow region and outward X-point in the outflow region at scale above 0.1 d i , corresponding to the electron inflow and outflow; whereas the decoupled ion velocities are very chaotic at such scales. (2) Around the X-line, the electron velocities can be very large. The electrons form an out-of-plane jet near the X-point, field-aligned stream at the magnetosphere-side separatrix region and in the inflow region, with velocities larger than 1000 km s −1 ; whereas the ion velocities are quite steady and generally below 250 km s −1 . (3) Both ion velocities and electron velocities are large in the magnetosphere, but small in the magnetosheath. These features reveal the different behaviors between ions and electrons around the X-line, which can significantly improve our understanding of the fundamental physics of the reconnection process. Moreover, the results well agree with classical theory, hence validating our scan technique and normalization method.
Source: The Astrophysical Journal
Institution: Beihang University
Language: English
Subfield: Space and Planetary Science
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,499
OpenAlex ID: W7222982584