Determine how shock-seeded vorticity fills the diffuse filament core

Determine how vorticity seeded at shock-bounded interfaces propagates inward to fill the diffuse core of a cosmic filament, including the roles of hierarchical proto-filament mergers and Kelvin–Helmholtz instabilities along sheared interfaces.

Background

The simulation identifies baroclinic vorticity generation at oblique accretion shocks and finds that vortex stretching later sustains the developed cascade. It does not, however, establish how the initially localized vorticity spreads through the diffuse filament core. The authors explicitly identify this transport mechanism as the second unresolved question, with hierarchical merging and Kelvin–Helmholtz instabilities proposed as candidate processes.

References

The second is how the vorticity seeded at the shock-bounded interfaces spreads inward to fill the diffuse core, with the hierarchical merging of the proto-filaments and the growth of Kelvin--Helmholtz instabilities along the sheared interfaces as natural candidate agents.

— The WEFT project: I. The emergence of turbulence in a cosmic filament  (2609.17205 - Lebeau et al., 15 Sep 2026) in Section 8.3, “Limitations and perspectives”