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Phenomenon of Alfvénic vortex shedding

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Gruszecki, M. (Marcin), Nakariakov, V. M. (Valery M.), Van Doorsselaere, Tom and Arber, T. D.. (2010) Phenomenon of Alfvénic vortex shedding. Physical Review Letters, Vol.105 (No.5). ISSN 0031-9007

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Official URL: http://dx.doi.org/10.1103/PhysRevLett.105.055004

Abstract

Generation of Alfvenic (magnetohydrodynamic) vortices by the interaction of compressible plasma flows with magnetic-field-aligned blunt obstacles is modeled in terms of magnetohydrodynamics. It is found that periodic shedding of vortices with opposite vorticity is a robust feature of the interaction in a broad range of plasma parameters: for plasma beta from 0.025 to 0.5, and for the flow speeds from 0.1 to 0.99 of the fast magnetoacoustic speed. The Strouhal number is the dimensionless ratio of the blunt body diameter to the product of the period of vortex shedding and the inflow speed. It is found to be consistently in the range 0.15-0.25 in the whole range of parameters. The induced Alfvenic vortices are compressible and contain spiral-armed perturbations of the magnetic field strength and plasma mass density up to 50%-60% of the background values. The generated electric current also has the spiral-armed structuring.

Item Type:	Journal Article
Subjects:	Q Science > QC Physics
Divisions:	Faculty of Science > Physics
Library of Congress Subject Headings (LCSH):	Magnetohydrodynamic waves, Vortex shedding
Journal or Publication Title:	Physical Review Letters
Publisher:	American Physical Society
ISSN:	0031-9007
Official Date:	30 July 2010
Volume:	Vol.105
Number:	No.5
Number of Pages:	4
Identification Number:	10.1103/PhysRevLett.105.055004
Status:	Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Restricted or Subscription Access
Funder:	Royal Society (Great Britain), British Academy (BA), Seventh Framework Programme (European Commission) (FP7)
Grant number:	NF090143 (BA/RS), 220555 (FP7)
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URI:	http://wrap.warwick.ac.uk/id/eprint/5451