  Measurements of the energy spectrum and of the vortex-density fluctuation
spectrum in superfluid turbulence seem to contradict each other. Using a
numerical model, we show that at each instance of time the total vortex line
density can be decomposed into two parts: one formed by metastable bundles of
coherent vortices, and one in which the vortices are randomly oriented. We show
that the former is responsible for the observed Kolmogorov energy spectrum, and
the latter for the spectrum of the vortex line density fluctuations.
