The solar dynamo is a physical process of magnetic field generation due to conversion of kinetic energy of plasma flows into magnetic energy. However, in the mean-field dynamo theory, one needs to segregate scales and consider separately large-scale dynamo and small-scale dynamo. The large-scale dynamo produces the large-scale mean field and unavoidable fluctuations of the mean field. Both are cycle-dependent. The small-scale dynamo is supposed to produce only the small-scale field, and this field is cycle-independent. There is no sharp boundary between the intervals of the large-scale and small-scale dynamos. An unavoidable presence of a smooth transition implies that there is a region where the properties of the large-scale global dynamo and fluctuations inherent to small-scale dynamo co-exist on some intermediate scales. Recent achievements in observations of the small-scale dynamo operation on the smallest observable scales and on the intermediate scales of typical active regions are discussed in the review.
