Shock location and CME 3D reconstruction of a solar type II radio burst with LOFAR

Zucca P, Morosan DE, Rouillard AP, Fallows R, Gallagher PT, Magdalenic J, Klein KL, Mann G, Vocks C, Carley EP, Bisi MM, Kontar EP, Rothkaehl H, Dabrowski B, Krankowski A, Anderson J, Asgekar A, Bell ME, Bentum MJ, Best P, Blaauw R, Breitling F, Broderick JW, Brouw WN, Brueggen M, Butcher HR, Ciardi B, De Geus E, Deller A, Duscha S, Eisloeffel J, Garrett MA, Griessmeier JM, Gunst AW, Heald G, Hoeft M, Horandel J, Iacobelli M, Juette E, Karastergiou A, Van Leeuwen J, Mckay-Bukowski D, Mulder H, Munk H, Nelles A, Orru E, Paas H, Pandey VN, Pekal R, Pizzo R, Polatidis AG, Reich W, Rowlinson A, Schwarz DJ, Shulevski A, Sluman J, Smirnov O, Sobey C, Soida M, Thoudam S, Toribio MC, Vermeulen R, Van Weeren RJ, Wucknitz O, Zarka P (2018)


Publication Status: Published

Publication Type: Journal article

Publication year: 2018

Journal

Publisher: EDP SCIENCES S A

Book Volume: 615

Article Number: ARTN A89

DOI: 10.1051/0004-6361/201732308

Abstract

Context. Type II radio bursts are evidence of shocks in the solar atmosphere and inner heliosphere that emit radio waves ranging from sub-meter to kilometer lengths. These shocks may be associated with coronal mass ejections (CMEs) and reach speeds higher than the local magnetosonic speed. Radio imaging of decameter wavelengths (20-90 MHz) is now possible with the Low Frequency Array (LOFAR), opening a new radio window in which to study coronal shocks that leave the inner solar corona and enter the interplanetary medium and to understand their association with CMEs.Aims. To this end, we study a coronal shock associated with a CME and type II radio burst to determine the locations at which the radio emission is generated, and we investigate the origin of the band-splitting phenomenon.Methods. The type II shock source-positions and spectra were obtained using 91 simultaneous tied-array beams of LOFAR, and the CME was observed by the Large Angle and Spectrometric Coronagraph (LASCO) on board the Solar and Heliospheric Observatory (SOHO) and by the COR2A coronagraph of the SECCHI instruments on board the Solar Terrestrial Relation Observatory (STEREO). The 3D structure was inferred using triangulation of the coronographic observations. Coronal magnetic fields were obtained from a 3D magnetohydrodynamics (MHD) polytropic model using the photospheric fields measured by the Heliospheric Imager (HMI) on board the Solar Dynamic Observatory (SDO) as lower boundary.Results. The type II radio source of the coronal shock observed between 50 and 70 MHz was found to be located at the expanding flank of the CME, where the shock geometry is quasi-perpendicular with theta(Bn)similar to 70 degrees. The type II radio burst showed first and second harmonic emission; the second harmonic source was cospatial with the first harmonic source to within the observational uncertainty. This suggests that radio wave propagation does not alter the apparent location of the harmonic source. The sources of the two split bands were also found to be cospatial within the observational uncertainty, in agreement with the interpretation that split bands are simultaneous radio emission from upstream and downstream of the shock front. The fast magnetosonic Mach number derived from this interpretation was found to lie in the range 1.3-1.5. The fast magnetosonic Mach numbers derived from modelling the CME and the coronal magnetic field around the type II source were found to lie in the range 1.4-1.6.

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Involved external institutions

Trinity College Dublin IE Ireland (IE) Astron NL Netherlands (NL) PSL Research University / Université de recherche Paris Sciences et Lettres FR France (FR) Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. (MPG) / Max Planck Society for the Advancement of Science DE Germany (DE) Linnaeus University (LNU) / Linnéuniversitetet SE Sweden (SE) University of Oxford GB United Kingdom (GB) University of Edinburgh GB United Kingdom (GB) University of Warmia and Mazury in Olsztyn PL Poland (PL) Rutherford Appleton Laboratory GB United Kingdom (GB) University of Manchester GB United Kingdom (GB) Institut de Recherche en Astrophysique et Planétologie (IRAP) FR France (FR) University of Glasgow GB United Kingdom (GB) Radboud University Nijmegen NL Netherlands (NL) Royal Observatory of Belgium / Koninklijke Sterrenwacht van België / Observatoire royal de Belgique BE Belgium (BE) Poznań Supercomputing and Networking Center / Poznańskie Centrum Superkomputerowo-Sieciowe PL Poland (PL) Eindhoven University of Technology / Technische Universiteit Eindhoven (TU/e) NL Netherlands (NL) Polska Akademia Nauk (PAN) / Polish Academy of Sciences PL Poland (PL) Universität Bielefeld DE Germany (DE) Thüringer Landessternwarte Tautenburg (TLS) - Karl-Schwarzschild-Observatorium DE Germany (DE) Max-Planck-Institut für Radioastronomie / Max Planck Institute for Radio Astronomy DE Germany (DE) Universitetet i Tromsø / The Arctic University of Norway (UiT) NO Norway (NO) University of Orléans / Université d'Orléans FR France (FR) Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum - GFZ DE Germany (DE) University of California Irvine US United States (USA) (US) Ruhr-Universität Bochum (RUB) DE Germany (DE) Curtin University AU Australia (AU) University of Technology Sydney (UTS) AU Australia (AU) Leibniz Institute for Astrophysics Potsdam / Leibniz-Institut für Astrophysik Potsdam DE Germany (DE) Universität Hamburg (UHH) DE Germany (DE) Australian National University (ANU) AU Australia (AU) Jagiellonian University / Uniwersytet Jagielloński (UJ) PL Poland (PL) Kapteyn Astronomical Institute NL Netherlands (NL) Rhodes University ZA South Africa (ZA) University of Groningen / Rijksuniversiteit Groningen NL Netherlands (NL)

How to cite

APA:

Zucca, P., Morosan, D.E., Rouillard, A.P., Fallows, R., Gallagher, P.T., Magdalenic, J.,... Zarka, P. (2018). Shock location and CME 3D reconstruction of a solar type II radio burst with LOFAR. Astronomy & Astrophysics, 615. https://dx.doi.org/10.1051/0004-6361/201732308

MLA:

Zucca, Pietro, et al. "Shock location and CME 3D reconstruction of a solar type II radio burst with LOFAR." Astronomy & Astrophysics 615 (2018).

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