EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

LOFAR observations of a jet-driven piston shock in the low solar corona

Ciara Maguire1,2, Eoin Carley2, Pietro Zucca3, Nicole Vilmer4,5, and Peter Gallagher2
Ciara Maguire et al.
  • 1School of Physics, Trinity College Dublin, Dublin 2, Ireland.
  • 2Astronomy & Astrophysics Section, Dublin Institute for Advanced Studies, Dublin, D02 XF86, Ireland.
  • 3ASTRON Netherlands Institute for Radio Astronomy, Dwingeloo, The Netherlands.
  • 4LESIA, Observatoire de Paris, PSL Research University, CNRS, Sorbonne Universités, UPMC Univ. Paris 06, Univ. Paris Diderot, Sorbonne Paris Cité, 5 place Jules Janssen, 92195 Meudon, France.
  • 5Station de Radioastronomie de Nançay, Observatoire de Paris, PSL Research University, CNRS, Univ. Orléans, 18330.

The Sun produces highly dynamic and eruptive events that can drive shocks through the corona. These shocks can accelerate electrons, which result in plasma emission in the form of a type II radio burst. Despite a large number of type II radio bursts observations, the precise origin of coronal shocks is still subject to investigation. Here we present a well-observed solar eruptive event that occurred on 16 October 2015, focusing on a jet observed in the extreme ultraviolet by the SDO Atmospheric Imaging Assembly, a streamer observed in white-light by the Large Angle and  Spectrometric Coronagraph, and a metric type II radio burst observed by the LOw-Frequency Array (LOFAR) radio telescope. For the first time, LOFAR has interferometrically imaged the fundamental and harmonic sources of a type II radio burst and revealed that the sources did not appear to be co-spatial, as would be expected from the plasma emission mechanism. We correct for the separation between the fundamental and harmonic using a model which accounts for the scattering of radio waves by electron density fluctuations in a turbulent plasma. This allows us to show the type II radio sources were located ∼0.5 Rsun above the jet and propagated at a speed of ∼1000 km s−1, which was significantly faster than the jet speed of ∼200 km s−1. This suggests that the type II burst was generated by a piston shock driven by the jet in the low corona.

How to cite: Maguire, C., Carley, E., Zucca, P., Vilmer, N., and Gallagher, P.: LOFAR observations of a jet-driven piston shock in the low solar corona, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7602,, 2021.

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