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Modelling astrophysical outflows via the unified dynamo-reverse dynamo mechanism.
- Source :
-
Monthly Notices of the Royal Astronomical Society: Letters . May2015, Vol. 449 Issue 1, pL36-L40. 5p. - Publication Year :
- 2015
-
Abstract
- The unified dynamo-reverse dynamo (Dy-RDy) mechanism, capable of simultaneously generating large-scale outflows and magnetic fields from an ambient microscopic reservoir, is explored in a broad astrophysical context. The Dy-RDy mechanism is derived via the Hall magnetohydrodynamics, which unifies the evolution of magnetic field and fluid vorticity. It also introduces an intrinsic length-scale, the ion skin depth, allowing for the proper normalization and categorization of microscopic and macroscopic scales. The large-scale Alfven Mach number MA, defining the relative 'abundance' of the flow field to the magnetic field is shown to be tied to a microscopic scalelength that reflects the characteristics of the ambient short-scale reservoir. The dynamo (Dy), preferentially producing the large-scale magnetic field, is the dominant mode when the ambient turbulence is mostly kinetic, while the outflow producing reverse dynamo (RDy) is the principal manifestation of a magnetically dominated turbulent reservoir. It is conjectured that an efficient RDy may be the source of many observed astrophysical outflows that have MA ≫ 1. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 17453925
- Volume :
- 449
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Monthly Notices of the Royal Astronomical Society: Letters
- Publication Type :
- Academic Journal
- Accession number :
- 102108792
- Full Text :
- https://doi.org/10.1093/mnrasl/slv017