magnetic field correlations then obey a set of nonlinear partial differential equations with the nonlinearity appearing as time-dependent co-efficients involving the average properties of the fluctuating field itself. In the sections which follow we apply these equations to study a number of astrophysically interesting problems.

We begin in section 5 by examining small-scale dynamo action in the galactic context. This problem was studied by KA who looked at the evolution of the magnetic energy spectrum in wavenumber space, taking the limit of large $k$ (small scales). In contrast to their treatment, the co-ordinate space approach adopted here, allows us to implement the boundary conditions for the magnetic correlation function, at both large and small-scales. Using the WKBJ approximation, we derive conditions for growth of small-scale fields in a model Kolmogorov turbulence and study the eigen functions for the longitudinal magnetic correlation (see below). Most earlier work also discussed small scale dynamo action for the case when the turbulent velocity has a single scale (cf. Kleeorin [*et al.*]{} 1986, Ruzmaikin [*et al.*]{} 1989 and references therein), Our work extends this to the context where multiple scales are present.

The nonlinear effects of ambipolar drift, on the small-scale dynamo are considered in 