"Spatial and temporal variability of dayside magnetopause reconnection" by Krishna Khanal

Date of Award

2025

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Space Science

Committee Chair

Gary Zank

Committee Member

Ying Zou

Committee Member

Qiang Hu

Committee Member

Lingling Zhao

Committee Member

Laxman Adhikari

Research Advisor

Gary Zank

Subject(s)

Magnetopause, Solar wind, Space environment

Abstract

The dissertation investigates the spatial and temporal variability of magnetopause reconnection, a central tenet of the solar wind-magnetosphere-ionosphere coupling. In the spatial sense, magnetopause reconnection occurs along X-lines of variable extent, which can be determined through remote sensing using ionospheric observations. Using in situ observations from Time History of Events and Macroscale Interactions during Substorms (THEMIS) in conjunction with ionospheric observations from the Super Dual Auroral Radar Network (SuperDARN), we conducted a statistical study to examine the variability and controlling factors of the spatial extent of magnetopause reconnection. Our findings indicate that the magnetopause X-lines can span from a few Earth radii (RE) to approximately 22 RE in the GSM-Y direction. Additionally, we observe that the X-lines tend to be spatially limited under high solar wind speed conditions. In the temporal sense, reconnection may be bursty or continuous. Continuous reconnection can also occur in an unsteady manner with a varying reconnection rate. A case of transient suppression of reconnection under significantly increased magnetospheric density is analyzed to investigate the underlying physical process that might be responsible.

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