Dissipative magnetic structures and scales in small-scale dynamos

ABSTRACT Small-scale dynamos play important roles in modern astrophysics, especially on galactic and extragalactic scales. Owing to dynamo action, purely hydrodynamic Kolmogorov turbulence hardly exists is often replaced by hydromagnetic turbulence. Understanding the size of dissipative magnetic structures estimating time-scale scintillation other observational theoretical aspects interstellar intergalactic small-scale dynamos. Here we show that, during kinematic phase dynamo, cutoff wavenumber energy spectra scales as expected for large Prandtl numbers, but continues same way also moderately small values – contrary what expected. For a critical number about 0.3, resistive cutoffs are found occur at wavenumber. In non-linearly saturated regime, becomes unity. The scale now has shallower scaling with below value three, steeper one otherwise compared regime.