Work

Ion-scale current sheets embedded in the reconnection-jet shear layer of the near-Sun heliospheric current sheet

Year: 2026

Type: article

Abstract: Context . Magnetic reconnection in the heliospheric current sheet (HCS) plays an important role in restructuring solar-wind magnetic topology and generating plasma jets and magnetic islands. While large-scale signatures of HCS reconnection have been reported in many observational studies, the kinetic-scale structure embedded within reconnection regions remains less well understood. Aims . We aim to investigate the ion-scale current sheets (CSs) embedded within an HCS reconnection region and their relationship to the flow-shear layer at the edge of a reconnection jet. Methods . We analyzed an HCS crossing observed by the Parker Solar Probe on March 29, 2024, using high-time-resolution magnetic-field measurements. We focused on ion-scale magnetic transitions within two brief intervals of flow shear layers at the edges of the reconnection jet and examined them in a local LMN coordinate system. Results . Twelve representative CSs are identified, whose duration is on average ∼0.06 s, corresponding to spatial scales of only a few ion inertial lengths. Eight of the twelve CSs exhibit localized bipolar variations in the transverse B M component, with several also showing bifurcated B L profiles characterized by plateau-like structure. In the remaining events, strong transverse fluctuations prevented the identification of a clear bipolar B M signature. Conclusions . The reconnection-jet shear layer in the HCS may serve as an active site that hosts a chain of ion-scale CSs. This provides new insight into the multiscale structure of HCS reconnection and suggests that flow shear layers may play an important role in generating secondary kinetic-scale structures.

Source: Astronomy and Astrophysics

DOI: 10.1051/0004-6361/202661982

Authors: Dae-Young Lee, Dooyoung Choi, Kyung-Eun Choi, Sung Jun Noh

Institutions: Chungbuk National University, Space Sciences Laboratory, New Mexico Consortium

Language: English

Topic: Solar and Space Plasma Dynamics

Subfield: Astronomy and Astrophysics

Field: Physics and Astronomy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,865

Funders: National Aeronautics and Space Administration, National Research Foundation, National Research Foundation of Korea, Ministry of Science and ICT, South Korea