Oscillations in the 45-5000 MHz Radio Spectrum of the 18 April 2014 Flare

0479175 - ASÚ 2018 RIV NL eng J - Článek v odborném periodiku
Karlický, Marian - Rybák, J. - Monstein, Ch.
Oscillations in the 45-5000 MHz Radio Spectrum of the 18 April 2014 Flare.
Solar Physics. Roč. 292, č. 7 (2017), 94/1-94/15. ISSN 0038-0938. E-ISSN 1573-093X
Grant CEP: GA ČR(CZ) GA16-13277S; GA ČR(CZ) GA17-16447S
Institucionální podpora: RVO:67985815
Klíčová slova: Sun flares * radio radiation * oscillations
Obor OECD: Astronomy (including astrophysics,space science)
Impakt faktor: 2.580, rok: 2017

Using a new type of oscillation map, made from the radio spectra by the wavelet technique, we study the 18 April 2014 M7.3 flare. We find a quasi-periodic character of this flare with periods in the range 65 - 115 seconds. At the very beginning of this flare, in connection with the drifting pulsation structure (plasmoid ejection), we find that the 65 - 115 s oscillation phase slowly drifts towards lower frequencies, which indicates an upward propagating wave initiated at the start of the magnetic reconnection. Many periods (1 - 200 seconds) are found in the drifting pulsation structure, which documents multi-scale and multi-periodic processes. On this drifting structure, fiber bursts with a characteristic period of about one second are superimposed, whose frequency drift is similar to that of the drifting 65 - 115 s oscillation phase. We also checked periods found in this flare by the EUV Imaging Spectrometer (EIS)/Hinode and Interface Region Imaging Spectrograph (IRIS) observations. We recognize the type III bursts (electron beams) as proposed, but their time coincidence with the EIS and IRIS peaks is not very good. The reason probably is that the radio spectrum is a whole-disk record consisting of all bursts from any location, while the EIS and IRIS peaks are emitted only from locations of slits in the EIS and IRIS observations.
Trvalý link: http://hdl.handle.net/11104/0275175