| Issue |
A&A
Volume 525, January 2011
|
|
|---|---|---|
| Article Number | A112 | |
| Number of page(s) | 7 | |
| Section | The Sun | |
| DOI | https://doi.org/10.1051/0004-6361/201015600 | |
| Published online | 06 December 2010 | |
Flare quasi-periodic pulsations with growing periodicity
1
Nobeyama Solar Radio Observatory / NAOJ,
Nagano
384-1305,
Japan
e-mail: reznik@nro.nao.ac.jp; shibasaki@nro.nao.ac.jp
2
Radiophysical Research Institute (NIRFI),
Nizhny Novgorod
603950,
Russia
Received:
17
August
2010
Accepted:
27
October
2010
We conducted a wavelet analysis of the flare intensity variations for the long duration flare on 2005 August 22 observed with the Nobeyama Radioheliograph at frequencies 17 and 34 GHz and with the Ramaty High Energy Solar Spectroscopic Imager at 25–50 keV. We found that the signals contain a well-pronounced periodicity in which the oscillation period grows from 2.5 to 5 min. An analysis of the loop length and plasma temperature evolution during the flare allowed us to interpret the quasi-periodic pulsations in terms of the second standing harmonics of the slow magnetoacoustic mode. This mode can be generated by the initial impulsive energy release and work as a trigger for the repeated energy releases.
Key words: magnetohydrodynamics (MHD) / waves / Sun: flares / Sun: oscillations / Sun: radio radiation / Sun: X-rays, gamma rays
© ESO, 2010
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