= Solution
<Internal intermittency> is the uneven distribution of activity within an already turbulent fluid: intense gradients and <viscous dissipation> occupy relatively small, fluctuating regions separated by much quieter regions. It concerns the internal field, rather than a turbulent/non-turbulent interface intermittently passing a probe.
<Integral-scale intermittency> is the variability of the energy-containing eddies and their local or time-dependent energy supply. Its modulation occurs on lengths and times of order $\ell$ and $\ell/u$, can depend strongly on forcing or initial conditions, and changes the background intensity experienced by smaller eddies.
Equilibrium-range intermittency concerns the increasing fluctuations of local transfer and <viscous dissipation> as the averaging scale is reduced below the <integral scale of turbulence>. It appears as non-Gaussian velocity-gradient statistics, fluctuating coarse-grained <viscous dissipation> and anomalous <longitudinal structure function> exponents. It includes the <inertial range> and its continuation into the <dissipation range>, where <kinematic viscosity> ultimately limits gradients. \b[Large-scale modulation varies the local energy supply; small-scale intermittency concentrates and redistributes that supply.] These effects can coexist, so they should not be identified simply because both broaden a distribution.
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