The Coupling Between Large-Scale Turbulent Fluctuations and Kinetic-Scale Instabilities

Collisionless plasmas, which characterize the majority of the heliosphere, including Earth’s magnetosheath and the solar wind, present a unique challenge to our understanding of plasma thermodynamics in space. In these environments, the absence of interparticle collisions means that energy redistribution and thermalization occur through kinetic-scale processes rather than classical viscosity or resistivity. While the macro-scale behavior of plasma turbulence has been studied extensively, the specific mechanisms by which energy cascades from fluid scales down to kinetic scales triggering kinetic microinstabilities remain a critical frontier in space plasma physics; in particular what concerns the ultimate dissipation of energy and plasma heating and selective particle acceleration. Temperature anisotropies and non-Maxwellian velocity distribution functions (VDFs) excite various wave modes that facilitate the conversion of turbulent energy into particle heat. Despite recent advancements in numerical modeling and high-resolution observations, the exact interplay between evolving turbulence and the onset of microinstabilities, and how this relationship dictates energy dissipation, is not sufficiently understood.This Research Topic aims to delve into the rather complex physics of energy conversion and dissipation within collisionless plasmas. We seek to understand how the synergy between plasma turbulence, kinetic microinstabilities (such as firehose, mirror, and electromagnetic ion cyclotron (EMIC) instabilities) and fluctuations shapes the state of the plasma. Exploring cross-scale interactions should contribute to the clarification of how energy is distributed on different scales as well as partitioned between different species in the multi-component space plasmas. The focus is on how microscopic processes affect the meso- and large-scale dynamics of the solar wind and the magnetospheric environment.We invite submissions that include, but are not limited to, the following areas:• Cross-scale energy transfer: The coupling between large-scale turbulent fluctuations and the triggering of kinetic-scale instabilities.• Identification of microinstabilities: Observational and simulation-based identification of ion and electron-scale instabilities (e.g., whistler, EMIC, and kinetic Alfvén waves).• Wave-particle interactions: Mechanisms of energy dissipation and the resulting signatures in particle VDFs, including non-Maxwellian features and beam formations.• Advanced diagnostic techniques: Application of advanced diagnostic methods like field-particle correlations to identify energy transfer in phase space.• Numerical Simulations: State-of-the-art simulations like particle-in-cell (PIC) and Vlasov simulations, to explore the non-linear evolution of turbulence and instabilities on various scales.• Role of discontinuities: The role of current sheets, shocks, and other discontinuities in mediating the coupling between large-scale turbulence and kinetic-scale instabilities.We encourage submission of original research articles, as well as timely reviews, and perspectives. Contributions employing diverse methodologies, theoretical analysis, comparative multi-spacecraft studies, and innovative numerical modeling, are highly welcome. Topic editors: Luca Sorriso-Valvo, Lingling Zhao, Rudolf A. Treumann Source: https://www.frontiersin.org/research-topics/81142/the-coupling-between-large-scale-turbulent-fluctuations-and-kinetic-scale-instabilities