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Electron scale coherent structure as micro accelerator in the Earth's magnetosheath
Zi-Kang Xie1, Qiu-Gang Zong2,3, Chao Yue1
1Institute of Space Physics and Applied Technology, Peking University, Beijing, 100871, China.
Nature Communications
|January 29, 2024
Summary
Turbulent energy dissipation in magnetized plasmas is clarified. A micro-accelerator model explains how electrons transform into streams, supported by MMS observations of coherent structures and electric fields.
Area of Science:
- Plasma Physics
- Space Physics
Background:
- Turbulent energy dissipation is a key, yet unresolved, process in plasma physics.
- It is widely accepted that dissipation at electron scales drives electron energization in magnetized plasmas.
Purpose of the Study:
- To propose a micro-accelerator model for electron distribution transformation.
- To explain electron energization and beam formation in magnetized plasmas.
Main Methods:
- Developed a micro-accelerator model incorporating field-aligned electric potential and mirror forces.
- Analyzed Magnetospheric Multiscale (MMS) observations of electron-scale coherent structures in the dayside magnetosheath.
Main Results:
- Identified an electron flux enhancement region within a coherent structure, associated with increased magnetic field strength and a parallel electric field.
- The proposed model successfully reproduces observed electron fluxes from ~50 eV to ~200 eV.
- Demonstrated the formation of bidirectional electron jets due to the structure's hourglass-like magnetic configuration.
Conclusions:
- The micro-accelerator model provides a viable mechanism for electron energization and Strahl distribution formation.
- Coherent structures with specific magnetic field configurations play a crucial role in particle acceleration and jet formation in space plasmas.
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