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Particle Acceleration by Magnetic Reconnection in Geospace
Mitsuo Oka1, Joachim Birn2,3, Jan Egedal4
1Space Sciences Laboratory, University of California Berkeley, 7 Gauss Way, Berkeley, 94720 CA USA.
Space Science Reviews
|November 16, 2023
Summary
Magnetic reconnection accelerates particles to high energies in Earth's magnetosphere. Recent studies reveal how structures like diffusion regions and magnetic islands contribute to this process, though further research on energy partition and turbulence is needed.
Area of Science:
- Space Physics
- Plasma Physics
- Astrophysics
Background:
- Magnetic reconnection is a key process in explosive energy-release phenomena in space plasmas.
- Its role in particle acceleration to non-thermal energies in Earth's magnetosphere is not fully understood.
Purpose of the Study:
- To review recent advancements in understanding particle acceleration by magnetic reconnection in Earth's magnetosphere.
- To identify areas requiring further investigation for a comprehensive understanding.
Main Methods:
- Analysis of data from recent spacecraft missions with improved resolutions.
- Application of the guiding-center approximation to study particle motion.
- Review of studies on parallel electric fields, Fermi, and betatron acceleration mechanisms.
Main Results:
- Detailed studies of particle acceleration at various structures: diffusion region, separatrix, jets, magnetic islands (flux ropes), and dipolarization front.
- Discussion on the relative importance of parallel electric fields, Fermi, and betatron effects.
Conclusions:
- Significant progress has been made in understanding particle acceleration via magnetic reconnection in Earth's magnetosphere.
- Further investigation is needed on energy partition and the role of turbulence to fully elucidate the acceleration mechanism and enable comparisons with solar and astrophysical environments.
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