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 the 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 (EUV) by the Atmospheric Imaging Assembly (SDO/AIA), a streamer observed in white-light by the Large Angle and Spectrometric Coronagraph (SOHO/LASCO), and a metric type II radio burst observed by the LOw Frequency Array (LOFAR). LOFAR 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 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 R⊙ above the jet and propagated at a speed of ∼1000 kms−1, which was significantly faster than the jet speed of ∼200 kms−1. This suggests that the type II burst was generated by a piston shock driven by the jet in the low corona.
@article{arxiv.2101.05569,
title = {LOFAR observations of a jet-driven piston shock in the low solar corona},
author = {Ciara A. Maguire and Eoin P. Carley and Pietro Zucca and Nicole Vilmer and Peter T. Gallagher},
journal= {arXiv preprint arXiv:2101.05569},
year = {2021}
}