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Kayoomars Karami

Kayoomars Karami

Academic rank: Professor
ORCID:
Education: PhD.
ScopusId: 22979495000
Faculty: Faculty of Science
Address: Department of Physics, University of Kurdistan Pasdaran St., P.O.Box: 66177-15175 Sanandaj - Iran
Phone:

Research

Title
Resonantly damped oscillations of elliptically shaped stratified emerging coronal loops
Type
JournalPaper
Keywords
Sun: corona · Sun: magnetic fields · Sun: oscillations
Year
2013
Journal ASTROPHYSICS AND SPACE SCIENCE
DOI
Researchers Kayoomars Karami ، Sirwan amiri ، Karam Bahari ، Zanyar Ebrahimi

Abstract

The effects of both elliptical shape and stage of emergence of the coronal loop on the resonant absorption of standing kink oscillations are studied. To do so, a typical coronal loop is modeled as a zero-beta longitudinally stratified cylindrical magnetic flux tube. We developed the connection formulae for the resonant absorption of standing transversal oscillations of a coronal loop with an elliptical shape, at various stages of its emergence. Using the connection formulae, the dispersion relation is derived and solved numerically to obtain the frequencies and damping rates of the fundamental and first-overtone kink modes. Our numerical results show that both the elliptical shape and stage of emergence of the loop alter the frequencies and damping rates of the tube as well as the ratio of frequencies of the fundamental and its first-overtone modes. However, the ratio of the oscillation frequency to the damping rate is not affected by the tube shape and stage of its emergence and also is independent of the density stratification parameter.