Non-linear dynamics in multi-phase, multi-component astrophysical systems
Prof. Kinwah Wu
Astrophysical systems are often complex and have many components. A galaxy cluster consists of dark matter, ionized gas and baryons that are trapped inside stars and galaxies. On a smaller scale, a galaxy consist of ionized gases, atomic/molecular gases, dusts as well as stars and substellar objects. Understanding how different components in a galaxy or a galaxy cluster interact with each other is non-trivial. There are many studies on the dynamics of galaxies, galaxy clusters and larger-scale structures, usually employing computationally intensive numerical simulations. These studies have put focus on gravitational interaction and mots of them are conducted in the context of galactic evolution and structural formation. While they have been successful in painting a broad picture of the universe, they fall short in quantifying much of the key underlying physics, thus we are not always able to test their models against experiments and observations with good confidence. This PhD project aims to address some of these issues by investigating the meso-scale interactions between different components in galaxies, galaxy clusters and larger-scale structures: e.g., whether or not streaming between two stellar populations or two gas phases could lead to bunching and instabilities, and how phase-transition fronts propagate in the universe that was being reionized. The objective is to determine how different interactions (gravitational or non-gravitational) give rise to different dynamical behaviours/phenomena and observational consequences. It is a theoretical project.