INSTANTON FOR RANDOM ADVECTION

A path integral over trajectories of 2n fluid particles is identified with a 2nth order correlation function of a passive scalar convected by d-dimensional short-correlated multiscale incompressible random velocity flow. Strong intermittency of the scalar is described by means of an instanton calculus (saddle point plus fluctuations about it) in the path integral at n\ensuremath{\gg}:d. The anomalous scaling exponent of the 2nth scalar's structural function is found analytically.