Christophe Gissinger
Associate professor at Ecole Normale Superieure (ENS Paris)

Waves are ubiquitous in both nature and industrial systems. Most of the time, they are closely related to the generation of instabilities in the flow. We use laboratory experiments to study the stability of such flows and the associated wave dynamics:


Astrophysical fluid dynamics deals with the application of fluid dynamics to the motion of fluids encountered in space, such as planetary or stellar interiors, accretion disks and galaxies. Thanks to the growing amount of telescope observations and space missions in recent years, whole sections of the theory of such flows are now actively debated. In our group, we combine laboratory experiments, theory and numerical modeling to understand the mechanisms involved in some of these astrophysical systems.

Hydrodynamics of ocean worlds: it is now very clear that subsurface oceanic worlds are ubiquitous. For instance, it is believed that a vast ocean of salty water is present beneath the surface of several moons and planets of the solar system (Ganymede, Europa, Enceladus, Ceres, Titan, etc). Although this is perhaps the most common type of oceanic world, hydrodynamics of such subsurface oceans remains mostly unknown. I recently started a project aiming to develop a unified oceanography model for such subsurface oceans.


Magnetic field generation: Part of my activity is to explore new mechanisms for the generation of planetary magnetic fields, such as the possibility of centrifugal instability in planetary interiors or the existence of new induction processes related to inhomogeneities of the fluid properties.


The study of turbulence is one of the most active research area. We developed several laboratory experiments in order to adress various questions related to turbulence, like the transport properties of turbulent flows, the dimensionality of turbulence or its statistical properties.

Turbulent transport: A long-standing question in fluid mechanics is to understand how angular momentum is transported by a turbulent flow. This question is also crucial for several celestial bodies. For instance, the exact mechanism by which the huge acccretion rates around black holes are generated is still unknown. Similarly, stellar interiors generally show rotation rates much slower than what is predicted by classical theories. I am therefore interested in the turbulent transport of angular momentum using both experimental and theoretical approaches.

lvks experiment
Tayler-Spruit dynamo

Coherent structures in turbulent flows and statistical physics: In many turbulent systems, an organized and coherent component of the velocity field, phase-correlated over the entire structure, appears on the top of the chaotic turbulent flow. The emergence and the dynamics of such coherent structures remains little understood. These structures can for instance be generated in 2D turbulence, when the flow is strongly constrained in one direction (rotating flows, thin layers, etc). Here are a few examples of what we are studying on this topic.


I also work on various non-linear problems, ranging from low-dimensional behavior in fluid dynamics to chaotic motions of mechanical systems. In general, one expects turbulent flows to show a very complex behavior, due to the infinite number of degrees of freedom. Yet, several turbulent systems, MHD or not, exhibit low-dimensional dynamics involving chaotic reversals between two symmetrical states. I work on deterministic or stochastic models aiming to understand such complex behaviors, using only a few modes in interaction.