Cooper, F. C. (Fenwick C.), Nakariakov, Valery M. and Tsiklauri, D.. (2003) Line-of-sight effects on observability of kink and sausage modes in coronal structures with imaging telescopes. Astronomy & Astrophysics, Vol.397 (No.2). pp. 765-770. ISSN 0004-6361

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Abstract

Kink modes of solar coronal structures, perturbing the loop in the direction along the line-of-sight (LOS), can be observed as emission intensity disturbances propagating along the loop provided the angle between the LOS and the structure is not ninety degrees. The effect is based upon the change of the column depth of the loop (along the LOS) by the wave. The observed amplitude of the emission intensity variations can be larger than the actual amplitude of the wave by a factor of two and there is an optimal angle maximizing the observed amplitude. For other angles this effect can also attenuate the observed wave amplitude. The observed amplitude depends upon the ratio of the wave length of kink perturbations to the width of the structure and on the angle between the LOS and the axis of the structure. Sausage modes are always affected negatively from the observational point of view, as the observed amplitude is always less than the actual one. This effect should be taken into account in the interpretation of wave phenomena observed in the corona with space-borne and ground-based imaging telescopes.

Item Type:	Journal Article
Subjects:	Q Science > QB Astronomy
Divisions:	Faculty of Science > Physics
Library of Congress Subject Headings (LCSH):	Sun -- Loop prominences, Sun -- Corona, Solar oscillations, Magnetohydrodynamic waves
Journal or Publication Title:	Astronomy & Astrophysics
Publisher:	EDP Sciences
ISSN:	0004-6361
Date:	January 2003
Volume:	Vol.397
Number:	No.2
Page Range:	pp. 765-770
Identification Number:	10.1051/0004-6361:20021556
Status:	Peer Reviewed
Access rights to Published version:	Open Access
Funder:	Particle Physics and Astronomy Research Council (Great Britain) (PPARC)
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URI:	http://wrap.warwick.ac.uk/id/eprint/3807

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