Fast Magnetoacoustic Waves in a Fan Structure Above a Coronal Magnetic Null Point

0391314 - ASÚ 2014 RIV NL eng J - Journal Article
Mészárosová, Hana - Dudík, Jaroslav - Karlický, Marian - Madsen, F.R.H. - Sawant, H. S.
Fast Magnetoacoustic Waves in a Fan Structure Above a Coronal Magnetic Null Point.
Solar Physics. Roč. 283, č. 2 (2013), s. 473-488. ISSN 0038-0938. E-ISSN 1573-093X
R&D Projects: GA ČR GAP209/12/0103
Grant - others:EU(XE) PIRSES-GA-2011-295272
Institutional support: RVO:67985815
Keywords : Sun: corona * flares * corona * radio radiation
Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics
Impact factor: 3.805, year: 2013

We analyze the 26 November 2005 solar radio event observed interferometrically at frequencies of 244 and 611 MHz by the Giant Metrewave Radio Telescope (GMRT) in Pune, India. Observations are used to make interferometric maps from 06:50 to 07:12 UT. The light curves of these sources show that only two sources at 244 MHz and 611 MHz are well correlated in time. Using SoHO/MDI observations and potential magnetic field extrapolation we demonstrate that both the correlated sources are located in the fan structure of magnetic field lines starting from a coronal magnetic null point. Wavelet analysis detects tadpoles with periods in the range P = 10 – 83 s. These wavelet tadpoles indicate the presence of fast magnetoacoustic waves that propagate in the fan structure of the coronal magnetic null point. We estimate the plasma parameters in radio sources and find them consistent with the presented scenario involving the coronal magnetic null point.
Permanent Link: http://hdl.handle.net/11104/0226057