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Collisionless ion-electron energy exchange in magnetized shocks
Y Zhang1,2, P V Heuer1, H Wen1
1University of Rochester, Laboratory for Laser Energetics, Rochester, New York 14623, USA.
Physical Review. E
|April 18, 2026
Summary
Collisionless shocks rapidly exchange energy between ions and electrons in magnetized plasma. Resonances between electron whistler and ion magnetohydrodynamic waves explain this faster-than-Coulomb energy transfer.
Area of Science:
- Plasma physics
- Astrophysical shocks
- Kinetic theory
Background:
- Energy partition in collisionless shocks remains a fundamental unsolved problem.
- Understanding ion-electron energy exchange is crucial for modeling astrophysical phenomena.
Purpose of the Study:
- Investigate the mechanism of rapid energy exchange between ions and electrons in magnetized collisionless shocks.
- Identify the physical processes responsible for faster-than-Coulomb energy transfer.
Main Methods:
- Performed kinetic simulations of magnetized collisionless shocks with moderate Alfvénic Mach number.
- Employed kinetic and multifluid models incorporating counter-streaming ions.
Main Results:
- Observed rapid, faster-than-Coulomb, energy exchange between ions and electrons in sufficiently magnetized plasmas.
- Identified specific wave resonances (electron whistler and ion magnetohydrodynamic waves) driving this energy transfer.
Conclusions:
- The study reveals a novel mechanism for energy partition in collisionless shocks.
- Wave-particle interactions, specifically resonances between electron whistler and ion magnetohydrodynamic waves, are key to rapid ion-electron energy exchange.
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