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

Abstract

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 $\sim$0.5 R${}_{\odot }$ above the jet and propagated at a speed of $\sim$1000 kms${}^{-1}$, which was significantly faster than the jet speed of $\sim$200 kms${}^{-1}$. This suggests that the type II burst was generated by a piston shock driven by the jet in the low corona.

References in corpus (8)

• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• The formation heights of coronal shocks from 2D density and Alfvén speed maps
• Quasiperiodic acceleration of electrons by a plasmoid-driven shock in the solar atmosphere
• Three-dimensional reconstruction of CME-driven shock-streamer interaction from radio and EUV observations: a different take on the diagnostics of coronal magnetic fields
• Evolution of the Alfvén Mach number associated with a coronal mass ejection shock
• First Observation of a Type II Solar Radio Burst Transitioning Between a Stationary and Drifting State
• Coronal turbulence and the angular broadening of radio sources - the role of the structure function
• Interferometric Imaging with LOFAR Remote Baselines of the Fine Structures of a Solar Type IIIb Radio Burst

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