  This report addresses an important question discussed by the quantum
turbulence community during the last decade: do quantized vortices form, in
zero-temperature superfluids, coherent structures similar to vortex tubes in
ordinary, viscous turbulence? So far the evidence provided by numerical
simulations is that bundles of quantized vortices appear in finite-temperature
superfluids, but from the interaction with existing coherent structures in the
turbulent (viscous) normal fluid, rather than due to the intrinsic superfuid
dynamics. In this report we show that, in very intense quantum turbulence
(whose simulation was made possible by a tree algorithm), the vortex tangle
contains small coherent vortical structures (bundles of quantized vortices)
which arise from the Biot-Savart dynamics alone, and which are similar to the
coherent structures observed in classical viscous turbulence.
