Fredagskollokvium: The challenge of simulating multiphase, turbulent gas

Many astrophysical systems, such as the interstellar, intracluster, or the circumgalactic medium, are multiphase with a colder phase embedded in a larger hot environment. Although ubiquitous, multiphase gas is notoriously hard to model which leads to often unconverged cold gas properties in large scale (cosmological) simulations. In such (turbulent) systems, hydrodynamical instabilities can destroy the cold gas on a short timescale. However, this mixing also leads to intermediate temperature gas which can radiatively cool and (re)form cold gas.
In this talk, I want to discuss under which conditions the cold gas can survive in a turbulent medium, and what sets the mass transfer between the phases. I will show that the survival criterion sets a characteristic scale of cold gas but the growth will lead to a scale-free mass distribution -- and that help simulating it might come from somewhat unexpected directions.