  Current understanding of the kinetic-scale turbulence in weakly-collisional
plasmas still remains elusive. We employ a general framework in which the
turbulent energy transfer is envisioned as a scale-to-scale Langevin process.
Fluctuations in the sub-ion range show a global scale invariance, thus
suggesting a homogeneous energy repartition. In this Letter, we interpret such
a feature by linking the drift term of the Langevin equation to scaling
properties of fluctuations. Theoretical expectations are verified on solar wind
observations and numerical simulations thus giving relevance to the proposed
framework for understanding kinetic-scale turbulence in space plasmas.
