Multiphase Gas Dynamics in Anisotropic Radiation Fields
Abstract
Over the last several years, we have extended the basic theory of thermal instability (TI) with a special focus on the non-linear regime where non-equilibrium and dynamical effects can be important. While our methods could be applied to studies of coronal rain flows, we have been focused on developing a quantitative physical model for astrophysical clouds in X-ray dominated environments with anisotropic radiation fields. We showed that in the absence of radiation forces, the nonlinear regime of TI results in condensations that are either isobaric or non-isobaric, the distinguishing feature of the latter regime being pronounced oscillations at a period proportional to the linear growth rate of TI. When the opacity to line scattering is non-negligible, we showed how to self-consistently account for the presence of radiation forces as TI saturates. Our time-dependent radiation-hydrodynamical (rad-HD) simulations thereby reveal how cloud acceleration, destruction, and evaporation (due to thermal conduction) accompanies cloud formation. These new developments enable us to address fundamental issues such as the expected cloud mass and size distributions, cloud interactions, and the spectral signatures of accelerated, clumpy plasmas.
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E.962P