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Particle injection in three-dimensional relativistic magnetic reconnection
Omar French1, Gregory R Werner1, Dmitri A Uzdensky2
1Center for Integrated Plasma Studies, Department of Physics, University of Colorado, 390 UCB, Boulder, CO 80309-0390, USA.
Journal of Plasma Physics
|March 2, 2026
Summary
Relativistic magnetic reconnection accelerates particles, but how they are injected is unclear. This study uses simulations to reveal how magnetisation affects injection energy and the roles of different acceleration mechanisms.
Area of Science:
- Plasma physics
- Astrophysics
- High-energy particle acceleration
Background:
- Relativistic magnetic reconnection is a key mechanism for non-thermal particle acceleration (NTPA), producing power-law spectra and high-energy emissions.
- Particle injection into NTPA, a critical but less-studied step, influences the observed power-law spectra and high-energy emissions.
Purpose of the Study:
- Investigate how upstream magnetisation influences particle injection energy.
- Quantify the contributions of direct electric field acceleration, Fermi kicks, and pickup acceleration to injected particles.
- Assess the impact of 2D vs. 3D simulations and instabilities on particle injection.
Main Methods:
- Utilizing fully kinetic particle-in-cell simulations.
- Systematically measuring injection energy across varying magnetisation parameters.
- Calculating the contributions of individual acceleration mechanisms to the injected particle population.
Main Results:
- Established a relationship between upstream magnetisation and injection energy.
- Quantified the relative importance of different injection mechanisms.
- Demonstrated the influence of dimensionality and instabilities on particle injection.
Conclusions:
- The study provides crucial insights into particle injection dynamics during relativistic magnetic reconnection.
- Findings advance our understanding of NTPA and its role in astrophysical phenomena.
- A theoretical model is presented to explain the simulation results.
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