Sub-Ion Scale Turbulence Driven by Magnetic Reconnection

The interplay between plasma turbulence and magnetic reconnection (MR) remains an unsettled question in astrophysical and laboratory plasmas. In this work we employ the spatial Coarse Graining (CG) method to study local energy transfer associated with MR, placing particular emphasis on the quantity πℓ(x) which allows to study the cross-scale energy transfer across scale ℓ and at position x.

Using both in-situ data and Hybrid Vlasov-Maxwell simulations, we report the first observational evidence that MR can drive sub-ion scale turbulence in magnetospheric plasmas, providing an effective alternative to the Kolmogorov fluid-like cascade. In particular the ion and the electron diffusion regions undergo an intense positive energy transfers to small scales, even when no transfer is observed at larger scales.

Lastly we speculate on the fate of the turbulent energy cascade and propose the value of the local transfer rate πℓ(x) at sub-ion scales as a measure indicative of localizedturbulent dissipation.