Numerical evidence for a small-scale dynamo approaching solar magnetic Prandtl numbers | Jörn Warnecke
Max Planck Institute for Solar System Research, Germany
Natural Sciences (Astrophysics and Astrononmy)
Magnetic fields on small scales are ubiquitous in the Universe. Although they can often be observed in detail, their generation mechanisms are not fully understood. One possibility is the so-called small-scale dynamo (SSD). Prevailing numerical evidence, however, appears to indicate that an SSD is unlikely to exist at very low magnetic Prandtl numbers (PrM) such as those that are present in the Sun and other cool stars. Here we have performed high-resolution simulations of isothermal forced turbulence using the lowest PrM values achieved so far. Contrary to earlier findings, the SSD not only turns out to be possible for PrM down to 0.0031 but also becomes increasingly easier to excite for PrM below about 0.05. Read more at https://espos.stream/2023/06/22/Warnecke/.
See publication in Nature Astronomy:
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