Precise evolution of turbulence at ion kinetic scales

Determine the precise evolution of solar-wind turbulence at ion kinetic scales, specifically characterizing how the turbulent cascade transitions across ion characteristic scales and how fluctuation properties change from magnetohydrodynamic scales to sub-ion kinetic scales.

Background

The paper studies solar-wind turbulence using Parker Solar Probe observations and focuses on the transition from magnetohydrodynamic scales to kinetic Alfvén wave (KAW) dominated regimes. While there is substantial evidence for KAWs at ion scales from observations and simulations, the detailed evolutionary pathway of the turbulence across ion kinetic scales is not yet established. This motivates the development of diagnostics and statistical analyses of magnetic helicity spanning inertial, transition, and kinetic-inertial ranges.

References

Despite substantial evidence of KAWs occurring at ion kinetic scales in satellite observations and numerical simulations, the precise evolution of turbulence at ion kinetic scales remains unknown.

— Observations of Transition from Imbalanced to Balanced Kinetic Alfvénic Turbulence  (2502.04764 - Zhao et al., 7 Feb 2025) in Introduction

The physical origin of this phenomenon is still unknown \citep{Nikos2025ApJ...993..142S}, therefore it is not implemented in the HSTM model at this time.

— A wavelet-based model of magnetic turbulence over a Parker spiral field  (2609.01206 - Larosa et al., 1 Sep 2026) in Section 4, subsection “Power spectral density”