Magnetohydrodynamic turbulence revisited

Goldreich, P.; Sridhar, S.

Please use this identifier to cite or link to this item: http://hdl.handle.net/2289/4861

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DC Field	Value	Language
dc.contributor.author	Goldreich, P.	-
dc.contributor.author	Sridhar, S.	-
dc.date.accessioned	2012-07-11T06:08:06Z	-
dc.date.available	2012-07-11T06:08:06Z	-
dc.date.issued	1997	-
dc.identifier.citation	The Astrophysical Journal, 1997, Vol.485, p680	en
dc.identifier.issn	0004-637X	-
dc.identifier.issn	1538-4357(Online)	-
dc.identifier.uri	http://hdl.handle.net/2289/4861	-
dc.description	Open Access	en
dc.description.abstract	In 1965, Kraichnan proposed that MHD turbulence occurs as a result of collisions between oppositely directed Alfvén wave packets. Recent work has generated some controversy over the nature of nonlinear couplings between colliding Alfvén waves. We find that the resolution to much of the confusion lies in the existence of a new type of turbulence, intermediate turbulence, in which the cascade of energy in the inertial range exhibits properties intermediate between those of weak and strong turbulent cascades. Some properties of intermediate MHD turbulence are the following: (1) in common with weak turbulent cascades, wave packets belonging to the inertial range are long-lived; (2) however, components of the strain tensor are so large that, similar to the situation in strong turbulence, perturbation theory is not applicable; (3) the breakdown of perturbation theory results from the divergence of neighboring field lines due to wave packets whose perturbations in velocity and magnetic fields are localized, but whose perturbations in displacement are not; (4) three-wave interactions dominate individual collisions between wave packets, but interactions of all orders n ≥ 3 make comparable contributions to the intermediate turbulent energy cascade; (5) successive collisions are correlated since wave packets are distorted as they follow diverging field lines; (6) in common with the weak MHD cascade, there is no parallel cascade of energy, and the cascade to small perpendicular scales strengthens as it reaches higher wavenumbers; (7) for an appropriate weak excitation, there is a natural progression from a weak, through an intermediate, to a strong cascade.	en
dc.language.iso	en	en
dc.publisher	The University of Chicago Press for the American Astronomical Society	en
dc.relation.uri	http://dx.doi.org/doi:10.1086/304442	en
dc.relation.uri	http://adsabs.harvard.edu/abs/1997ApJ...485..680G	en
dc.relation.uri	http://arxiv.org/abs/astro-ph/9612243	en
dc.rights	1997 American Astronomical Society	en
dc.title	Magnetohydrodynamic turbulence revisited	en
dc.type	Article	en
Appears in Collections:	Research Papers (A&A)

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