Phase Transition Dynamics of The Interstellar Medium: Theory, Methodology, and Implications
Abstract
The magnetohydrodynamics (MHD) of the interstellar medium are remarkably different from those of simple barotropic gas owing to the phase transitions between cold and warm phases (and hot phase) that trigger a variety of instabilities. Identification of distinct instabilities at various stages provide us important clues for understanding the saturation levels of turbulent energies and the rates of formation and destruction of cold clouds such as HI clouds and molecular clouds. Recent progress in this line of theoretical research based on numerical simulations is outlined. Numerical simulation of the phase transition dynamics of the interstellar medium requires the description of very different length scales, from sub-pc “Field length” to the Galactic scale, using shock-capturing high-resolution schemes for MHD. Various techniques to improve the accuracy of numerical schemes based on the method of characteristics are outlined, including an approximate nonlinear Riemann Solver for MHD and a piece-wise exact solution method for multi-timescale physics.
- Publication:
-
Numerical Modeling of Space Plasma Flows ASTRONUM-2014
- Pub Date:
- October 2015
- Bibcode:
- 2015ASPC..498...75I