Short quasi-periodic MHD waves in coronal structures
UNSPECIFIED (2005) Short quasi-periodic MHD waves in coronal structures. SPACE SCIENCE REVIEWS, 121 (1-4). pp. 115-125. ISSN 0038-6308Full text not available from this repository.
Official URL: http://dx.doi.org/10.1007/s11214-006-4718-8
The possibility of remote diagnostics of coronal structures with impulsively-generated short-period fast magnetoacoustic wave trains is demonstrated. An initially broad-band, aperiodic fast magnetoacoustic perturbation guided by a 1D plasma inhomogeneity develops into a quasi-periodic wave train with a well-pronounced frequency and amplitude modulation. The quasi-periodicity results from the geometrical dispersion of the modes, determined by the transverse profile of the loop, and hence contains information about the profile. Wavelet images of the wave train demonstrate that their typical spectral signature is of a "crazy tadpole'' shape: a narrow spectrum tail precedes a broad-band head. The instantaneous period of the oscillations in the wave train decreases gradually with time, with a mean value of several seconds for typical coronal values. The period and the spectral amplitude evolution are determined by the steepness of the transverse density profile and the density contrast ratio in the loop, which offers a tool for estimation of the sub-resolution structuring of the corona.
|Item Type:||Journal Item|
|Subjects:||Q Science > QB Astronomy|
|Journal or Publication Title:||SPACE SCIENCE REVIEWS|
|Official Date:||December 2005|
|Number of Pages:||11|
|Page Range:||pp. 115-125|
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