Work

In Situ Observations of Particle Energization during the Coalescence of Magnetic Flux Ropes at Earth’s Magnetopause

Year: 2026

Type: article

Abstract: Coalescence of magnetic flux ropes (MFRs) is an efficient pathway for particle acceleration and energy conversion during magnetic reconnection. However, the associated particle energization mechanism and energy partition remain poorly understood. Using Magnetospheric Multiscale (MMS) observations of two coalescing MFRs at Earth’s magnetopause, we quantitatively evaluate electron and ion energization across distinct energy ranges. We find that electron energization was dominated by a parallel electric field within the thermal population, while ion energization was primarily governed by Fermi and betatron mechanisms within both thermal and suprathermal populations. The suprathermal energization fraction was significantly larger for ions than for electrons, indicating distinct acceleration pathways and energy partitions between the two species during MFR coalescence. These results improve our understanding of species- and energy-dependent energization during MFR coalescence.

Source: The Astrophysical Journal

DOI: 10.3847/1538-4357/aea61b

Authors: Wenqing Ma, Hui Zhu, Zhihong Zhong

Institutions: Shandong University, Nanchang University

Language: English

Topic: Ionosphere and magnetosphere dynamics

Subfield: Space and Planetary Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $4,499

Funders: National Natural Science Foundation of China, Natural Science Foundation of Shandong Province