Fluid dynamics in astrophysics and cosmology

Fluid mechanics is a fundamental tool for the sciences of the Universe: from the Earth and giant planets to stars, accretion disks and the interstellar medium, it is an essential approach for studying astrophysical objects. The "Fluid Dynamics in Astrophysics and Cosmology" course is a deepening of the "Hydrodynamics" course organized around 3 central themes in astrophysics: rotating fluids, thermal convection, and magnetohydrodynamics.

- Be able to describe an astrophysical problem using the equations of fluid mechanics

- Know the main properties of rotating flows, thermal convection and magnetohydrodynamic flows

- Know how to apply a stability analysis to an astrophysical problem

The general objective of this course is to be able to approach the M2 courses of stellar astrophysics and interstellar medium which largely involve hydrodynamics and magnetohydrodynamics.

- Hydrodynamics

- Mathematical tools

Final test

1. Rotating fluids

◦ equations and characteristic numbers

◦ geostrophic flow

◦ inertial waves and Rossby waves

◦ effects of viscosity

2. Thermal convection

◦ conductive balance

◦ Boussinesq approximation and anelastic approximation

◦ baroclinicity

◦ Schwarzschild criterion and Rayleigh-Benard instability

◦ Ledoux criterion and thermohaline convection.

3. Magnetohydrodynamics

◦ reminders about the motion of charged particles in a magnetic field

◦ fluid approximation for plasma description and equations of motion

◦ remarkable properties of MHD flows

◦ frozen field, magnetic pressure and voltage, field-without-force, equipartition

◦ Alfven waves and magnetosonors

◦ the problem of the dynamo

- An introduction to fluid dynamics, M. Rieutord, De Boeck, 2014

- Astrophysics for physicists, A.R. Choudhuri, Cambridge University Press, 2010