Generation of large-scale magnetic fields by small-scale dynamo in shear flows
- Princeton Univ., NJ (United States). Dept. of Astrophysical Sciences; Max Planck & Princeton Ctr Plasma Phys, Princeton, NJ 08543 USA; Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); California Inst. of Technology (CalTech), Pasadena, CA (United States)
- Princeton Univ., NJ (United States). Dept. of Astrophysical Sciences; Max Planck & Princeton Ctr Plasma Phys, Princeton, NJ 08543 USA; Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
We propose a new mechanism for a turbulent mean-field dynamo in which the magnetic fluctuations resulting from a small-scale dynamo drive the generation of large-scale magnetic fields. This is in stark contrast to the common idea that small-scale magnetic fields should be harmful to large-scale dynamo action. These dynamos occur in the presence of a large-scale velocity shear and do not require net helicity, resulting from off-diagonal components of the turbulent resistivity tensor as the magnetic analogue of the "shear-current" effect. Furthermore, given the inevitable existence of nonhelical small-scale magnetic fields in turbulent plasmas, as well as the generic nature of velocity shear, the suggested mechanism may help explain the generation of large-scale magnetic fields across a wide range of astrophysical objects.
- Research Organization:
- Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC02-09CH11466; AC02-09-CH11466
- OSTI ID:
- 1259593
- Alternate ID(s):
- OSTI ID: 1224124
- Report Number(s):
- PPPL-5148; PRLTAO
- Journal Information:
- Physical Review Letters, Vol. 115, Issue 17; ISSN 0031-9007
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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