Links between turbulence and small-scale proton microinstabilities

Establish the nature of the links between turbulence and small-scale kinetic microinstabilities affecting protons, characterising how turbulent fluctuations interact with these instabilities and influence proton energisation.

Background

The authors review recent efforts exploring connections between turbulence and microinstabilities for protons, including hybrid simulations of Alfvénic turbulence and solar wind observations. Despite this progress, the relationship remains unresolved.

This open problem motivates the paper’s fluid-level approach to assess energy conversion (via j·E′) near instability thresholds and to relate turbulence-driven fluctuations to kinetic regulation of proton velocity distribution functions.

References

The links between turbulence and small-scale instabilities have recently started to be explored for the protons, for example in hybrid simulations of Alfvénic turbulence and in the solar wind. However, this is still an open problem.

— Turbulent Energy Conversion Associated with Kinetic Microinstabilities in Earth's Magnetosheath (2407.20844 - Lewis et al., 30 Jul 2024) in Section 1 (Introduction)