Space is expanding so fast it should rip plasma apart, but a fundamental cooling trick still works.
April 17, 2026
Original Paper
Landau damping on expanding backgrounds
arXiv · 2604.14911
The Takeaway
Landau damping is a vital process where plasma—the stuff inside stars and fusion reactors—settles down without its particles ever touching. For the first time, scientists proved this happens even as the entire universe is stretching out like a balloon. It is like finding out a ripple in a pond still behaves the same way even if the pond is growing into an ocean. This bridges the gap between the tiny world of atoms and the massive scale of the cosmos. It helps us understand how the very first structures in the universe didn't just vibrate themselves to pieces.
From the abstract
We analyse the effect of expansion in Newtonian cosmology on the asymptotic behaviour of charged self-interacting plasmas close to Poisson equilibria. To this end, we study the Vlasov-Poisson system on the phase space of a $3$-torus which is expanding with respect to the scale factor $a(t)$. We show that, for $a(t)=t^q$ with $q\in(0,\frac12)$, solutions to this system exhibit nonlinear Landau damping for initial data that is small with respect to a suitably strong Gevrey class, i.e., the charge