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 an extension 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

- Understand the main properties of rotational flows, thermal convection and magnetohydrodynamic flows

- Apply stability analysis to an astrophysical problem

The general aim of this course is to enable you to take M2 courses in stellar astrophysics and the interstellar medium, which largely involve hydrodynamics and magnetohydrodynamics.

- Hydrodynamics

- Mathematical tools

Final inspection

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-Bénard instability

◦ Ledoux criterion and thermohaline convection

3. Magnetohydrodynamics

◦ recalls 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, force-free field, equipartition

◦ Alfven waves and magnetosonors

◦ the dynamo problem

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

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