LOFAR tied-array imaging of Type III solar radio bursts - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Astronomy and Astrophysics - A&A Year : 2014

LOFAR tied-array imaging of Type III solar radio bursts

1 Trinity College Dublin
2 AIP - Leibniz-Institut für Astrophysik Potsdam
3 RAL - STFC Rutherford Appleton Laboratory
4 LESIA - Laboratoire d'études spatiales et d'instrumentation en astrophysique
5 IRA - Institute of Radio Astronomy of NAS of Ukraine
6 LLNL - Lawrence Livermore National Laboratory
7 IWF - Space Research Institute of Austrian Academy of Sciences
8 IRF - Swedish Institute of Space Physics [Uppsala / Kiruna]
9 SRON - SRON Netherlands Institute for Space Research
10 Jacobs University = Constructor University [Bremen]
11 University of Southampton
12 RSAA - Research School of Astronomy and Astrophysics [Canberra]
13 Max Planck Institute for Astrophysics
14 Hamburger Sternwarte/Hamburg Observatory
15 ASTRON - Netherlands Institute for Radio Astronomy
16 TLS - Thüringer Landessternwarte Tautenburg
17 Radboud University [Nijmegen]
18 LAGRANGE - Joseph Louis LAGRANGE
19 Leiden Observatory [Leiden]
20 USN - Unité Scientifique de la Station de Nançay
21 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
22 RUB - Ruhr University Bochum = Ruhr-Universität Bochum
23 MPIFR - Max-Planck-Institut für Radioastronomie
24 AI PANNEKOEK - Astronomical Institute Anton Pannekoek
25 CRAL - Centre de Recherche Astrophysique de Lyon
26 NRAO - National Radio Astronomy Observatory [Charlottesville]
27 School of Physics and Astronomy [Southampton]
28 LASP - Laboratory for Atmospheric and Space Physics [Boulder]
29 UP11 - Université Paris-Sud - Paris 11
30 CfA - Harvard-Smithsonian Center for Astrophysics
D. E. Morosan
  • Function : Author
P. Zucca
  • Function : Author
R. Fallows
  • Function : Author
E. P. Carley
  • Function : Author
G. Mann
J. Magdalenić
  • Function : Author
H. Reid
  • Function : Author
J. Anderson
  • Function : Author
A. Asgekar
  • Function : Author
M. J. Bentum
  • Function : Author
G. Bernardi
P. Best
  • Function : Author
J. Bregman
  • Function : Author
F. Breitling
  • Function : Author
J. E. Conway
  • Function : Author
E. de Geus
  • Function : Author
S. Duscha
  • Function : Author
J. Eislöffel
C. Ferrari
A. W. Gunst
  • Function : Author
T. E. Hassall
  • Function : Author
J. W. T. Hessels
  • Function : Author
A. Horneffer
  • Function : Author
M. Iacobelli
A. Karastergiou
  • Function : Author
M. Kramer
  • Function : Author
P. Maat
  • Function : Author
H. Munk
  • Function : Author
H. Paas
  • Function : Author
G. Pietka
  • Function : Author
R. Pizzo
H. Röttgering
D. Schwarz
  • Function : Author
M. Serylak
  • Function : Author
O. Smirnov
  • Function : Author
B. W. Stappers
  • Function : Author
O. Wucknitz
  • Function : Author

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. 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. The Sun was imaged with 126 simultaneous tied-array beams within 5 solar radii 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. Over a period of 30 minutes, multiple Type III radio bursts were observed, a number of which were found to be located at high altitudes (4 solar radii 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. 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.
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Dates and versions

insu-01336001 , version 1 (20-11-2018)

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D. E. Morosan, P. T. Gallagher, P. Zucca, R. Fallows, E. P. Carley, et al.. LOFAR tied-array imaging of Type III solar radio bursts. Astronomy and Astrophysics - A&A, 2014, 568 (A67), ⟨10.1051/0004-6361/201423936⟩. ⟨insu-01336001⟩
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