Nonlinear Generation of Fluting Perturbations by Kink Mode

M S Ruderman

doi:10.1007/s11207-017-1133-0

Nonlinear Generation of Fluting Perturbations by Kink Mode

Sol Phys. 2017;292(8):111. doi: 10.1007/s11207-017-1133-0. Epub 2017 Aug 11.

Author

M S Ruderman^{1

2}

Affiliations

¹ 1Solar Physics and Space Plasma Research Centre (SP²RC), School of Mathematics and Statistics, University of Sheffield, Hicks Building, Hounsfield Road, Sheffield, S3 7RH UK.
² 2Space Research Institute (IKI), Russian Academy of Sciences, Moscow, Russia.

Abstract

We study the excitation of fluting perturbations in a magnetic tube by an initially imposed kink mode. We use the ideal magnetohydrodynamic (MHD) equations in the cold-plasma approximation. We also use the thin-tube approximation and scale the dependent and independent variables accordingly. Then we assume that the dimensionless amplitude of the kink mode is small and use it as an expansion parameter in the regular perturbation method. We obtain the expression for the tube boundary perturbation in the second-order approximation. This perturbation is a superposition of sausage and fluting perturbations. The amplitude of the fluting perturbation takes its maximum at the middle of the tube, and it monotonically decreases with the distance from the middle of the tube.

Keywords: Magnetic fields; Magnetohydrodynamics; Oscillations; Sun, corona; Waves.