Coupling of specific plasma processes to turbulent dynamics in collisionless plasmas

Determine how specific plasma processes couple into turbulent dynamics in collisionless plasmas and lead to energy dissipation and particle energisation, identifying the mechanisms and pathways responsible for this coupling.

Background

The paper investigates energy conversion signatures (j·E′) associated with kinetic microinstabilities in Earth’s magnetosheath using MMS observations. A central motivation is to better understand how microphysical processes within collisionless plasmas connect to macroscopic turbulent dynamics and result in dissipation and particle energisation.

By quantifying enhanced non-ideal energy conversion near temperature anisotropy–beta instability thresholds, the work aims to shed light on this broader unresolved question of process–turbulence coupling in collisionless environments.

References

This work provides insight into the open question of how specific plasma processes couple into the turbulent dynamics and ultimately lead to energy dissipation and particle energisation in collisionless plasmas.

— Turbulent Energy Conversion Associated with Kinetic Microinstabilities in Earth's Magnetosheath  (2407.20844 - Lewis et al., 2024) in Abstract (page 1)

The physical mechanism of this coupling is not entirely elucidated and requires dedicated investigations that are out of the scope of this article.

— Helicon wave propagation, plasma generation and interaction with low-frequency waves in toroidal magnetic configurations  (2609.18883 - Vincent et al., 16 Sep 2026) in Section 4.2, “Interaction with low-frequency waves”

The three-dimensional spatial structure and the dynamics of turbulence in weakly collisional plasmas are major scientific unknowns in our understanding of plasma physics.

— In-situ measurements of space plasma: recent progress and future challenges  (2608.16734 - Verscharen, 17 Aug 2026) in Section 4.2, “HelioSwarm”

Turbulence and shock problem: What role does reconnection play in related processes such as turbulence, collisionless shocks, and plasma transport? Is reconnection an integral part of magnetized turbulence? Is turbulence a solution for multi-scale reconnection? How does reconnection facilitate particle acceleration in collisionless shocks?

— The FLARE Facility  (2608.17332 - Ji et al., 18 Aug 2026) in Section 5, Future Upgrades and Collaborative Research

The local $\beta$ in our measurement region is much larger than that in the reconnection upstream and is comparable to the conditions in the turbulent magnetosheath in which electron-only reconnection is observed, so it is natural to ask whether the same coupling operates there. If it does, electron-only reconnection---usually regarded as a sink for energy---could couple to ions in the outflow and re-inject wave energy at scales near the electron Larmor radius, with wave-vectors nearly perpendicular to the local magnetic field. The smaller separation between current sheets in electron-only reconnection may also allow such waves to interact with neighboring layers and occupy a larger fraction of the volume than in standard electron-ion reconnection. Testing this will require measurements that resolve the wave-vector as well as the frequency, which is beyond the scope of the present work.

— Excitation of the lower-hybrid drift instability in the outflow of electron-only magnetic reconnection  (2608.20299 - Russell et al., 20 Aug 2026) in Conclusion, final paragraph

The second is that we assumed zero heat flux for the 10-moment MHD model. Implementing a more realistic heat flux, such as the closure for Landau damping , is required to understand kinetic effects in large-scale systems.

— A generalized energy-consistent finite difference scheme for 10-moment magnetohydrodynamics  (2608.25441 - Akutagawa et al., 26 Aug 2026) in Section 6, Conclusion