The effects of density stratification on standing fast body oscillations in coronal loops and dissipation |
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Authors: | K Karami A Asvar |
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Institution: | Department of Physics, University of Kurdistan, Pasdaran Street, PO Box 66177-15175, Sanandaj, Iran;Research Institute for Astronomy &Astrophysics of Maragha (RIAAM), PO Box 55134-441, Maragha, Iran;Institute for Advanced Studies in Basic Sciences (IASBS), Gava Zang, PO Box 45195-1159, Zanjan, Iran |
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Abstract: | The standing magnetohydrodynamic (MHD) quasi-linear modes in a zero-β cylindrical magnetic flux tube that undergoes a longitudinal density stratification and radial density structuring are considered. The radial structuring is assumed to have a step-like density profile. The dispersion relation for the fast MHD body waves is derived and solved numerically to obtain the frequencies of the fundamental, first-overtone and second-overtone k = 1, 2, 3 modes of both kink ( m = 1) and fluting ( m = 2) waves, where k and m are the longitudinal and azimuthal mode numbers, respectively. Damping rates due to both viscous and resistive dissipations in the presence of the density stratification are derived and solved numerically for the first three modes of both kink and fluting waves. |
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Keywords: | Sun: corona Sun: magnetic fields Sun: oscillations |
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