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Persistent URL	http://purl.org/net/epubs/work/12315026
Record Status	Checked
Record Id	12315026
Title	LOFAR tied-array imaging of Type III solar radio bursts
Contributors	DE Morosan, PT Gallagher, P Zucca, R Fallows, EP Carley, G Mann, MM Bisi (STFC Rutherford Appleton Lab.), A Kerdraon, AA Konovalenko, AL MacKinnon, HO Rucker, B Thidé, J Magdaleni?, C Vocks, H Reid, J Anderson, A Asgekar, IM Avruch, MJ Bentum, G Bernardi, P Best, A Bonafede, J Bregman, F Breitling, J Broderick, M Brüggen, HR Butcher, B Ciardi, JE Conway, F de Gasperin, E de Geus, A Deller, S Duscha, J Eislöffel, D Engels, H Falcke, C Ferrari, W Frieswijk, MA Garrett, J Grießmeier, AW Gunst, TE Hassall, JWT Hessels, M Hoeft, J Hörandel, A Horneffer, M Iacobelli, E Juette, A Karastergiou, VI Kondratiev, M Kramer, M Kuniyoshi, G Kuper, P Maat, S Markoff, JP McKean, DD Mulcahy, H Munk, A Nelles, MJ Norden, E Orru, H Paas, M Pandey-Pommier, VN Pandey, G Pietka, R Pizzo, AG Polatidis, W Reich, H Röttgering, AMM Scaife, D Schwarz, M Serylak, O Smirnov, BW Stappers, A Stewart, M Tagger, Y Tang, C Tasse, S Thoudam, C Toribio, R Vermeulen, RJ van Weeren, O Wucknitz, S Yatawatta, P Zarka
Abstract	The Sun is an active source of radio emission which is often associated with energetic phenomena such as solar flares and coronal mass ejections (CMEs). At low radio frequencies (<100 MHz), the Sun has not been imaged extensively because of the instrumental limitations of previous radio telescopes. Aims. Here, the combined high spatial, spectral, and temporal resolution of the LOw Frequency ARray (LOFAR) was used to study solar Type III radio bursts at 30–90 MHz and their association with CMEs. Methods. The Sun was imaged with 126 simultaneous tied-array beams within ?5 R? of the solar centre. This method offers benefits over standard interferometric imaging since each beam produces high temporal (~83 ms) and spectral resolution (12.5 kHz) dynamic spectra at an array of spatial locations centred on the Sun. LOFAR’s standard interferometric output is currently limited to one image per second. Results. Over a period of 30 min, multiple Type III radio bursts were observed, a number of which were found to be located at high altitudes (~4 R? from the solar center at 30 MHz) and to have non-radial trajectories. These bursts occurred at altitudes in excess of values predicted by 1D radial electron density models. The non-radial high altitude Type III bursts were found to be associated with the expanding flank of a CME. Conclusions. The CME may have compressed neighbouring streamer plasma producing larger electron densities at high altitudes, while the non-radial burst trajectories can be explained by the deflection of radial magnetic fields as the CME expanded in the low corona.
Organisation	STFC , RALSP
Keywords	Sun: coronal mass ejections (CMEs) , Sun: particle emission , Sun: corona , Sun: radio radiation
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Language	English (EN)

Type	Details	URI(s)	Local file(s)	Year
Journal Article	Astron Astrophys 568 (2014): A67.	doi:10.1051/0004-6361/201423936		2014