Turbulence and magnetic fields in diffuse molecular gas:
from 30-pc to mpc scales
Falgarone, E. and Hily-Blant, P.
The pressure of the diffuse interstellar medium is dominated by turbulent and magnetic contributions. Turbulent dissipation and decoupling of gas from magnetic fields are therefore critical to its evolution. Statistical observations of the velocity-field of diffuse molecular gas in different environments reveal the strong coupling operated by turbulence between scales. The non-Gaussianities of the velocity-field are found to be those of space-time intermittency, a fundamental property of turbulence: the regions where turbulent dissipation is concentrated are not distributed randomly in space but organized in thin parsec-scale coherent structures. New results on these coherent structures include : (1) their mpc-scale sub-structure and link with magnetic field topology, (2) their role in triggering chemistry, and (3) their seeding the growth of filaments in molecular clouds.