Issue |
A&A
Volume 488, Number 2, September III 2008
|
|
---|---|---|
Page(s) | 757 - 761 | |
Section | The Sun | |
DOI | https://doi.org/10.1051/0004-6361:200809873 | |
Published online | 24 June 2008 |
Standing fast magnetoacoustic kink waves of solar coronal loops with field-aligned flow
1
Group of Astrophysics and Gravity Theory, Institute of Physics, UMCS, ul. Radziszewskiego 10, 20-031 Lublin, Poland e-mail: marcingruszecki@wp.pl
2
The Catholic University of America, NASA Goddard Space Flight Centre, Code 671, Greenbelt, MD 20771, USA
Received:
30
March
2008
Accepted:
6
June
2008
Aims.
We refer to the recent observational data of Hinode,
which detected weakly-attenuated coronal loop
oscillations in the presence of background flow (Ofman & Wang 2008, A&A, 482, L9).
Vertical loop oscillations that lasted for three wave periods
were reported with a wave period P = 113 ± 2 s, attenuation time τ = 560 ± 260 s, and
wave amplitude = 0.67 ± 0.12 Mm.
Ofman & Wang (2008) estimated the flow speed within the range of 74–123 km s-1.
We consider impulsively generated standing fast magnetoacoustic kink waves
of a straight solar coronal slab with field-aligned internal flow.
We aim to determine the influence of such flow on the spatial and temporal signatures of these waves.
Methods. The time-dependent, ideal magnetohydrodynamic equations are solved numerically.
Results. The numerical results show that as a result of wave scattering on inhomogeneous flow
kink waves experience stronger attenuation than for a still plasma,
while P remains weakly altered by this flow.
Numerically evaluated values of and P
are close to the observational data. A value of
is about two times smaller than
observed.
Key words: magnetohydrodynamics (MHD) / Sun: corona / Sun: oscillations
© ESO, 2008
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