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Magnetotail reconnection onset caused by electron kinetics with a strong external driver
San Lu1, Rongsheng Wang2,3, Quanming Lu4,5
1Department of Earth, Planetary, and Space Sciences and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, CA, USA.
Nature Communications
|October 8, 2020
Summary
Magnetotail reconnection begins with electron-scale events when a strong external driver is present. These electron reconnection events then evolve into ion-scale reconnection, clarifying geospace energy conversion.
Area of Science:
- Geophysics
- Plasma Physics
- Space Science
Background:
- Magnetotail reconnection is vital for geospace energy conversion.
- The onset mechanism of magnetotail reconnection remains a long-standing debate.
- Key questions involve external drivers versus spontaneous instability on electron or ion scales.
Purpose of the Study:
- To investigate the onset mechanism of magnetotail reconnection.
- To determine if reconnection initiates on electron or ion scales.
- To clarify the role of external drivers in reconnection onset.
Main Methods:
- Utilized in-situ spacecraft observations.
- Performed particle-in-cell (PIC) simulations.
- Analyzed electron and ion scale kinetics during reconnection.
Main Results:
- Magnetotail reconnection was initiated by electron reconnection under a strong external driver.
- Electron reconnection was observed to develop into ion reconnection.
- Direct evidence linking electron kinetics and external drivers to reconnection onset was found.
Conclusions:
- Magnetotail reconnection onset is driven by electron kinetics in the presence of strong external drivers.
- Electron-scale reconnection precedes ion-scale reconnection in this scenario.
- Findings resolve decades of controversy regarding reconnection initiation.
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