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arXiv · 2112.15518

Collapsing-ring blowup solutions for the Keller-Segel system in three dimensions and higher

Charles Collot·Tej-Eddine Ghoul·Nader Masmoudi·Van Tien Nguyen
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Abstract

We consider the parabolic-elliptic Keller-Segel system in three dimensions and higher, corresponding to the mass supercritical case. We construct rigorously a solution which blows up in finite time by having its mass concentrating near a ring that shrinks to a point. In particular, the singularity is of type II, non self-similar. We show the stability of this dynamics among spherically symmetric solutions. In renormalised variables, the solution ressembles a traveling wave imploding at the origin, and this, to our knowledge, is the first stability result for such phenomenon for an evolution PDE. We develop a framework to handle the interactions between the two blowup zones contributing to the mechanism: a thin inner zone around the ring where viscosity effects occur, and an outer zone where the evolution is mostly inviscid.

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Charles Collot, Tej-Eddine Ghoul, Nader Masmoudi, Van Tien Nguyen. 2021-12-31. Collapsing-ring blowup solutions for the Keller-Segel system in three dimensions and higher. https://arxiv.org/abs/2112.15518

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