In astrophysics and cosmology, fluid flow occurs on a large range of scales and under very different conditions, from the dense interior of stars and planets to the highly rarefied intergalactic medium. These flows share the fact that they are generally turbulent, i.e. highly disordered both in space and time.
Most astrophysical flows occur under conditions where the driving forces generate large fluctuations in velocity and pressure with important consequences for the transport of energy and mass. Turbulence is one of the key processes for the structure and evolution of a large variety of geo- and astrophysical systems.
Astrophysical turbulence and instabilities occur in connection with rotation, convection, and magnetic fields. The universality of astrophysical turbulence interlinks the physics of the interior of planets or stars with protoplanetary or galactic disks, as well as the intergalactic gas outside of galaxies. For example, angular momentum transport by turbulence is a central question that must be answered to understand how galaxies or stars form, how protoplanetary disks evolve, how metals are mixed in the interstellar and intergalactic medium, or how differential rotation is established in stars and planets.
Magnetic field amplification through turbulent dynamo processes is ubiquitous in planets, stars, and galaxies. The onset of instabilities due to dust particles or newly formed planets in protoplanetary disks controls the properties of the evolving structures. We can observe a variety of interactions between stars, planets and galaxies with their environment leading to the exchange of energy and (angular-) momentum.
This compilation highlights the enormous potential and perspective of a collaborative effort to investigate the common underlying physical processes. Our combination of prohects will enable us to understand aspects of turbulent magnetic field amplification, turbulence and instabilities of rotating fluids, and in the interaction of turbulence and instabilities with radiation, gravitation, or dust particles and hence answer fundamental questions about the formation and evolution of galaxies, stars, and planets.