Throughout this talk, I will introduce shock physics and explore their role in the interstellar medium (ISM) thanks to observational, simulated and theoretical illustrations.
Typical velocities in the ISM are within an order of magnitude of the sound speed. Shocks should therefore be a ubiquitous component of this turbulent gas.
Ordered kinetic energy is converted into heat inside a shock's working surface, the thermal collisions excite the gas and the excitation energy is then radiated away in their wake. Shocks should then be one of the most efficient ways to probe dissipation in our galaxy. However, their unambiguous observational characterisation has remained elusive in the dilute ISM.
Shocks compress the gas and the magnetic fields: they are in part responsible for the equipartition between the magnetic and kinetic energies, and may impact the relative density and magnetic structures as seen in Planck's foregrounds.
Last but not least, the local temperature rise in shocks help to overcome energy barriers and open new chemical routes for the formation of molecules. Recent molecular observations in high-z galaxies may thus trace the dissipation of turbulent gas.