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Our attention focuses on the stochastic dynamo equation with non-normaloperator that give an insight into the role of stochastics and non-normality inthe galactic magnetic field generation. The main point of this Letter is adiscussion of the generation of a large-scale magnetic field that cannot beexplained by traditional linear eigenvalue analysis. We present a simplestochastic model for the thin-disk axisymmetric $\alpha \Omega $ dynamoinvolving three factors: (a) the non-normality generated by differentialrotation, (b) the nonlinearity reflecting how the magnetic field affects theturbulent dynamo coefficients, and (c) stochastic perturbations. We show thateven for \textit{subcritical case,} there are three possible mechanisms for thegeneration of magnetic field. The first mechanism is a deterministic one thatdescribes an interplay between transient growth and nonlinear saturation of theturbulent $\alpha -$effect and diffusivity. It turns out that the trivial stateis nonlinearity unstable to small but finite initial perturbations. The secondand third are the stochastic mechanisms that account for the interaction ofnon-normal effect generated by differential rotation and random additive andmultiplicative fluctuations. In particular, we show that in \textit{subcriticalcase}the average magnetic energy can grow exponentially with time due to themultiplicative noise associated with $\alpha -$effect.Comment: 7 pages, 2 figure

Non-normal and stochastic amplification of magnetic energy in the turbulent dynamo: Subcritical case