The multifractal nature of solar magnetism and the solar dynamo problem
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Based on observation data with a high spatial resolution, the multifractal properties of turbulent magnetized plasma in a nonperturbed solar atmosphere are revealed. It is shown that magnetic fluxes in elements of the magnetic field, as well as the size of elements, are distributed lognormally, which is indicative of multifractality. In coronal holes (CHs), the multifractality of magnetic fields is observed on scales of 10000-400 km; at the same time, it is observed on smaller scales as the resolution improves, and its degree increases. It is shown that two subsets of granules exist: the usual granules, with a characteristic size of 1000–1300 km and Gaussian size distribution, and mini-granules, which do not have a well-pronounced characteristic size and are mostly less than 600 km in diameter. The size distribution function of the mini-granules obeys lognormal law and their multifractal character is seen on small scales down to 50 km, which allows one to make a conclusion about the presence of multifractality of photospheric plasma flows in CHs and in a nonperturbed photosphere. A conclusion is made that multifractality takes place for small-scale magnetic fields of quiet regions, as well as for large-scale fields of active regions. This makes it possible to suppose that solar magnetic fields are generated by a common nonlinear dynamical process.
KeywordsSolar Magnetic Field Multifractality Spectrum Quiet Region Solar Magnetism Thick Gray Line
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