TY - JOUR

T1 - Motion of axisymmetric magnetic eddies with swirl

AU - Hattori, Yuji

AU - Smith, Stefan G.Llewellyn

N1 - Funding Information:
This research was supported by Collaborative Research Project 2010 and 2011, Institute of Fluid Science, Tohoku University, Project Code J10022 and J11029.

PY - 2013

Y1 - 2013

N2 - We consider the motion of axisymmetric magnetic eddies with swirl in ideal magnetohydrodynamic (MHD) flow. The magnetic field is assumed to be toroidal, while the velocity field has both toroidal and poloidal components. The contour-dynamics formulation by Hattori and Moffatt (2006) for the case without swirl is extended to include swirl velocity so that the cross helicity does not vanish in general. The strength of the vortex sheets that appear on the contours varies with time under the influence of the centrifugal force due to swirl and the magnetic tension due to the Lorentz force. Numerical simulation using the contour-dynamics formulation shows that there exist counter-propagating dipolar structures whose radius is given by a balance between the centrifugal force and the magnetic tension. These structures are well described by the steady solutions obtained by perturbation expansion. The effects of vorticity inside the eddy on the motion of eddies are also investigated.

AB - We consider the motion of axisymmetric magnetic eddies with swirl in ideal magnetohydrodynamic (MHD) flow. The magnetic field is assumed to be toroidal, while the velocity field has both toroidal and poloidal components. The contour-dynamics formulation by Hattori and Moffatt (2006) for the case without swirl is extended to include swirl velocity so that the cross helicity does not vanish in general. The strength of the vortex sheets that appear on the contours varies with time under the influence of the centrifugal force due to swirl and the magnetic tension due to the Lorentz force. Numerical simulation using the contour-dynamics formulation shows that there exist counter-propagating dipolar structures whose radius is given by a balance between the centrifugal force and the magnetic tension. These structures are well described by the steady solutions obtained by perturbation expansion. The effects of vorticity inside the eddy on the motion of eddies are also investigated.

KW - Contour dynamics

KW - Cross helicity

KW - Magnetohydrodynamics (MHD)

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U2 - 10.1016/j.piutam.2013.03.028

DO - 10.1016/j.piutam.2013.03.028

M3 - Conference article

AN - SCOPUS:84876500479

VL - 7

SP - 243

EP - 250

JO - Procedia IUTAM

JF - Procedia IUTAM

SN - 2210-9838

T2 - IUTAM Symposium on Topological Fluid Mechanics II

Y2 - 23 July 2012 through 27 July 2012

ER -