Journal ArticleDOI
Wave propagation in a magnetic cylinder
P. M. Edwin,B. Roberts +1 more
TLDR
In this article, the authors investigated the nature of oscillations in a magnetic cylinder embedded in magnetic environment and showed that the standard slender flux tube analysis of a kink mode in a cylinder excludes the possibility of a second mode, which arises under photospheric conditions.Abstract:
The nature of oscillations in a magnetic cylinder embedded in a magnetic environment is investigated. It is shown that the standard slender flux tube analysis of a kink mode in a cylinder excludes the possibility of a second mode, which arises under photospheric conditions. Under coronal conditions, two widely separated classes of oscillation can be freely sustained, one on an acoustic time-scale and the other on an Alfvenic time-scale. The acoustic-type oscillations are always present, but the much shorter period, Alfvenic-type, oscillations arise only in high density (strictly, low Alfven velocity) loops. An application to waves in fibrils is also given, and suggests (following Wentzel, 1979) that they are fast kink waves propagating in a density enhancement.read more
Citations
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Journal ArticleDOI
Propagating kink waves in thin twisted magnetic tubes with continuous equilibrium magnetic field
TL;DR: In this article, the dispersion equations for propagating kink waves and for unstable perturbations in the long wavelength approximation were derived, which implies that there are no unstable long kink modes.
Journal ArticleDOI
Observation of standing kink waves in solar spicules
TL;DR: In this article, the authors analyzed the time series of Ca ii H-line obtained from Hinode/SOT on the solar limb and showed that the observed oscillation may correspond to the fundamental harmonic of standing kink waves.
Journal ArticleDOI
Standing kink oscillations of thin twisted magnetic tubes with continuous equilibrium magnetic field
TL;DR: In this paper, the authors derived the governing integral equation that determines the eigenfrequencies and eigenmodes of the tube kink oscillations, and analyzed the corrections to the frequencies of the fundamental mode and first overtone of a straight magnetic tube related to the presence of twist.
Journal ArticleDOI
Fast magnetohydrodynamic oscillations in an elliptical coronal arcade
TL;DR: In this article, a model of an elliptically shaped coronal arcade with piecewise constant density is discussed to explore the effects of curvature on radially polarised fast modes.
Journal ArticleDOI
Fundamental and Harmonic Oscillations in Neighboring Coronal Loops
Abstract: We present observations of multimode (fundamental and harmonic) oscillations in a loop system, which appear to be simultaneously excited by a GOES C-class flare. Analysis of the periodic oscillations reveals that (1) the primary loop with a period of P-a approximate to 4 minutes and a secondary loop with two periods of Pa approximate to 4 minutes and Pb approximate to 2 minutes are detected simultaneously in closely spaced loop strands; (2) both oscillation components have their peak amplitudes near the loop apex, while in the second loop the low-frequency component Pa dominates in a loop segment that is two times larger than the high-frequency component Pb; (3) the harmonic mode Pb shows the largest deviation from a sinusoidal loop shape at the loop apex. We conclude that multiple harmonic modes with different displacement profiles can be excited simultaneously even in closely spaced strands, similar to the overtones of a violin string.
References
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Journal ArticleDOI
Elastic Waves in Layered Media
TL;DR: In this paper, Elastic Waves in Layered Media (ELMW) are used to describe the properties of layered media in a geologiska foreningen i Stockholm Forhandlingar.
Journal ArticleDOI
Wave propagation in a magnetically structured atmosphere
TL;DR: In this paper, the authors investigate the occurrence of magnetoacoustic surface waves at a single magnetic interface and consider in detail the case where one side of the interface is field-free.
Journal ArticleDOI
Wave propagation in a magnetically structured atmosphere: III: The slab in a magnetic environment
P.M. Edwin,B. Roberts +1 more
TL;DR: In this paper, the propagation of waves in a magnetic slab embedded in magnetic environment is investigated and possible modes of propagation are examined from the general dispersion relation, both analytically and numerically, for disturbances which are evanescent in the environment.