The Effect of Twisted Magnetic Field on the Period Ratio P_1/P_2 of Nonaxisymmetric MHD Waves

Abstract

The nonaxisymmetric magnetohydrodynamic (MHD) modes in a zero-beta cylindrical compressible thin magnetic flux tube modelled as a twisted core surrounded by a magnetically twisted annulus, both embedded in a straight ambient external field is considered. The dispersion relation is derived and solved analytically and numerically to obtain the frequencies of the nonaxisymmetric MHD waves. The main result is that the twisted magnetic annulus does affect the period ratio P_1/P_2 of the kink modes. For the kink modes, the magnetic twist in the annulus region can achieve deviations from P_1/P_2 = 2 of the same order of magnitude as in the observations. Furthermore, the effect of the internal twist on the fluting modes is investigated.

20 pages, 10 figures, 1 table

References in corpus (6)

• On the nature of kink MHD waves in magnetic flux tubes
• The effect of twisted magnetic field on the resonant absorption of MHD waves in coronal loops
• TRACE Observations of Driven Loop Oscillations
• The effects of twisted magnetic field on coronal loops oscillations and dissipation
• The effect of density stratification on the resonant absorption of MHD waves in coronal loops
• Torsional Alfven waves in stratified and expanding magnetic flux tubes

Cited by in corpus (14)

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• The effect of a twisted magnetic field on the phase mixing of the kink magnetohydrodynamic waves in coronal loops
• Resonant absorption of kink oscillations in coronal flux tubes with continuous magnetic twist
• The effect of magnetic twist on resonant absorption of slow sausage waves in magnetic flux tubes
• The Effect of Flow and Magnetic Twist on Resonant Absorption of Slow MHD Waves in Magnetic Flux Tubes
• Transverse kink oscillations of inhomogeneous prominence threads: numerical analysis and H$\alpha$ forward modelling
• Observation of the period ratio P_1/P_2 of transversal oscillations in solar macro-spicules
• Torsional Alfven waves and the period ratio P_1/P_2 in spicules
• The period ratio P_1/P_2 of torsional Alfvén waves with steady flows in spicules
• Resonant Absorption of Kink MHD Waves in Inclined and Asymmetric Coronal Loops
• Resonantly damped oscillations of elliptically shaped stratified emerging coronal loops