Dynamo is a threshold phenomenon Weak dynamo drivers

Dynamo is a threshold phenomenon Weak dynamo drivers magnetic field decays Intensive dynamo drivers magnetic field self-excitation Zeldovich 1956 – temporary growth in between Still insufficiently investigated. Our aim to investigate it for the case of small -scale dynamo

Kazantsev 1967 model Short correlation time (important). No mirror-asymmetry (for simplicity only).

Two statements of the problem ¬ 1. Persistent seed magnetic field (say, geomagnetic field in a dynamo experiment). ¬ 2. A localized initial condition. ¬Two substantially different behaviours.

Persistent seed. Quite similar to a dynamo

Seed at the beginning only – growth and decay

Conclusions ¬Turbulent motions and Rm (based at the vortex scale) about 20 – a promising area of dynamo exeriments. ¬Important for some astrophysical situations – dwarf galaxies and solar/stellar surface