The Magnetic Prandtl number (Prm) is a dimensionless quantity occurring in magnetohydrodynamics which approximates the ratio of momentum diffusivity (viscosity) and magnetic diffusivity.[1] It is defined as:


At the base of the Sun's convection zone the Magnetic Prandtl number is approximately 10−2,[2] and in the interiors of planets and in liquid-metal laboratory dynamos is approximately 10−5.

See also


  1. ^ Schekochihin, Alexander A.; Cowley, Steven C.; Maron, Jason L.; McWilliams, James C. (2004-02-03). "Critical Magnetic Prandtl Number for Small-Scale Dynamo". Physical Review Letters. 92 (5): 054502. arXiv:astro-ph/0308336. Bibcode:2004PhRvL..92e4502S. doi:10.1103/physrevlett.92.054502. ISSN 0031-9007. PMID 14995310. S2CID 119389465.
  2. ^ Schumacher, Jörg; Sreenivasan, Katepalli R. (7 October 2020). "Colloquium: Unusual dynamics of convection in the Sun". Reviews of Modern Physics. 92 (4): 041001. Bibcode:2020RvMP...92d1001S. doi:10.1103/RevModPhys.92.041001. S2CID 225111979. Retrieved 17 April 2021.