国立天文台で翌週に開催されるセミナーの情報をとりまとめ、webとE-mail(semiinfo)でご案内しています。 台内の研究教育活動の情報交換や、台外との研究交流の促進等にご活用ください。 Each week we use this web site and the (semiinfo) email list to announce seminars to be held at NAOJ campuses in the upcoming week. Please inform us of your research and educational meetings so that we can include them.
Flare quasi-periodic pulsations with growing periodicity
Abstract
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 thesignals 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.