ИСТИНА

Stars similar to the Sun demonstrate super-flares, which are considerably more powerful than solar flares. It is believed that the magneticfield energies of these stars are much higher than that of the Sun. The present study attempts to explain such an anomalously high magnetic energy by resonance phenomena related to the stellar dynamo, which involve significant changes in the behavior of the solutions subject to certain external effects and satisfy certain parametric relationships. These resonance phenomena are studied using low-mode models for a dynamo occurring in two or one spherical shells. It is shown that resonance effects arising in these models can result in increases of the magnetic energies by one and a half orders of magnitude compared with nonresonance cases. It is also shown that resonance dynamo conditions can differ considerably from the simple resonance conditions used for oscillating systems. This can probably be explained by the fact that the excitation and propagation of magnetic waves in dynamo problems are closely connected with each other, so that the resonance equations remain nonlinear even when they are maximally simplified. We also investigate Earth-like dynamo with positive dynamo number. For a suitable parametric range the model demonstrates magnetic field excitation in form of vacillations, dynamo bursts and even stationary magnetic configurations. A resonance can be expected if magnetic field penetrates from one dynamo active shell into another or for a periodic modulation of dynamo drivers. In both cases we isolate some resonant phenomena mainly in the form of a resonant absorption. The results obtained are however quite remote from naive expectations and the problem seems to deserve a more extended investigation.