Issue |
A&A
Volume 402, Number 2, May I 2003
|
|
---|---|---|
Page(s) | L17 - L20 | |
Section | Letters | |
DOI | https://doi.org/10.1051/0004-6361:20030448 | |
Published online | 14 April 2003 |
Letter to the Editor
Slow-mode standing waves observed by SUMER in hot coronal loops
Max-Planck-Institut für Aeronomie, 37191 Katlenburg-Lindau, Germany
Corresponding author: T. J. Wang, wangtj@linmpi.mpg.de
Received:
12
March
2003
Accepted:
25
March
2003
We report the first detection of postflare loop oscillations seen in both
Doppler shift and intensity. The observations were recorded in an
line by the SUMER spectrometer on SOHO in the corona about 70 min after an M-class flare on the solar limb. The oscillation has a period
of about 17 min in both the Doppler velocity and the intensity, but their decay
times are different (i.e., 37 min for the velocity and 21 min for
the intensity). The fact that the velocity and the intensity oscillations
have exactly a 1/4-period phase difference points to the existence
of slow-mode standing waves in the oscillating loop. This interpretation is also
supported by two other pieces of evidence: (1) the wave period and
(2) the amplitude relationship between the intensity and velocity are as
expected for a slow-mode standing wave.
Key words: Sun: corona / flares / oscillations / UV radiation
© ESO, 2003
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