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Title: Why is the two-dimensional inverse energy cascade non-intermittent?
Plain: In three-dimensional turbulence rare violent events dominate high-order statistics, but the energy flow to large scales in flat turbulence shows no growth of such events with decreasing scale. The reason for this difference is not known.
Precise: In the inverse energy cascade of forced 2D Navier-Stokes turbulence, velocity-increment exponents are $\zeta_p = p/3$ within error, and increment distributions are self-similar though measurably non-Gaussian (Boffetta, Celani, Vergassola 2000). Explain the absence of anomalous scaling from the dynamics, and determine whether small deviations exist at high order or for other forcing protocols.
Settled by: A theory predicting $\zeta_{p} = p/3$ or specific small corrections, checked against DNS at resolutions above $16384^{2}$.
Kind: phenomenon
Answer type: mechanism
References: (empty)
Literature status: open
Status note: (empty)
Posed since: 2000