The critical role of magnetic helicity in astrophysical large-scale dynamos
نویسنده
چکیده
The role of magnetic helicity in astrophysical large-scale dynamos is reviewed and compared with cases where there is no energy supply and an initial magnetic field can only decay. In both cases magnetic energy tends to get redistributed to larger scales. Depending on the efficiency of magnetic helicity fluxes, the decay of a helical field can speed up. Likewise, the saturation of a helical dynamo can speed up through magnetic helicity fluxes. The astrophysical importance of these processes is reviewed in the context of the solar dynamo and an estimated upper limit for the magnetic helicity flux of 10 Mx/cycle is given.
منابع مشابه
Astrophysical magnetic fields and nonlinear dynamo theory
The current understanding of astrophysical magnetic fields is reviewed with particular emphasis on nonlinear dynamo theory. Analytic and numerical results are discussed both for small scale dynamos, where helicity is unimportant, and for large scale dynamos, where kinetic helicity is crucial. Large scale dynamos produce small scale magnetic helicity as a waste product that quenches the large sc...
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