Factors contributing to the conservation of magnetic helicity |
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| Authors: | Manuel Nú?ez |
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| Institution: | Department of Mechanics and Materials Science , The Johns Hopkins University , Baltimore, Md., 21218 |
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| Abstract: | The magnetic helicity is often considered a quasi-invariant in the magnetohydrodynamic evolution of a plasma. While in general this is not the case, this invariance phenomenon occurs in many relevant situations, so that it is interesting to look for physical parameters that may detract from the maximum theoretical decay rate of helicity. The size of the Lorentz force is the main one: based on it, we find that several means of the magnetic energy, the transfer rate between kinetic and magnetic energies, and the variation of the angular momentum tend to slow down the evolution of magnetic helicity. |
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| Keywords: | Magnetic helicity Energy Integral inequalities |
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