Journal of Statistical Physics, Vol. 77, Nos. 3/4, 1994, p. 909-914.
Corrections of Batchelor's spectral law "- 1" of passive scalar fluctuations are obtained by taking into account the topological instabilities of small-scale vortex sheets: "-4/3" for supercritical and "-5/4"' for subcritical regimes. The corresponding fractal dimensions of the scalar interface are D, = 8/3 for supercritical and D, = 11/4 for subcritical regimes. Good agreement with experimental data is established.