A review on scaling laws in turbulent space plasmas

In turbulent plasma flows, nonlinear interactions among velocity and magnetic field fluctuations drive a cascade of energy from large to small scales, resulting in broadband spectra and inhomogeneous dissipative structures.
Despite their inherently stochastic character, the global statistical properties of such fluctuations obey precise scaling laws, which represent an important class of universality of turbulent processes.
The scaling law of the third-order moment, known in neutral fluids since the 1950s, has been formally derived for magnetohydrodynamic flows in 1998 in a basic version, and validated in space plasmas a decade later.
Following the first validations, an outburst of theoretical, numerical and observational studies expanded the validity of the law to plasma-specific contexts, and allowed us to evaluate the turbulent energy dissipation, a quantity of difficult estimation in collisionless plasmas.
The results provided by a large number of studies are crucial for the correct modeling of solar wind and magnetospheric plasma dynamics, and ultimately to understand the way collisionless plasmas dissipate energy.
The main results of the last quarter of a century are now critically described in a bulky review article recently published in Physics Reports (available for free download until February 15, 2023) and co-authored by ISTP researcher Luca Sorriso-Valvo.


Raffaele Marino and Luca Sorriso-Valvo, Scaling laws for the energy transfer in space plasma turbulence, Physics Reports 1006, 1-144, 2023, https://doi.org/10.1016/j.physrep.2022.12.001.

Artist’s impression of the ESA Solar Orbiter spacecraft (from www.esa.int) and inferred scaling law.