Fine and superfine structure of Decameter-Hectometer type II burst on 2011 June 7

TL;DR

This study analyzes the fine and superfine structures of a type II solar radio burst with herringbone features observed in 2011, revealing detailed polarization, frequency structures, and associating it with a CME event.

Contribution

It provides the first observation of second-order fine frequency structures in herringbone sub-bursts and links the burst to a CME on the flank of a shock.

Findings

First observation of second-order fine frequency structure in herringbone sub-bursts

Determined the CME's direction and speed using STEREO and SOHO data

Identified the burst source location on the shock flank

Abstract

The characteristics of the type II bursts with herringbone structure observed both by ground based radio telescopes (UTR-2, URAN-2) and spaceborn spectrometers (STEREO A-B) are discussed. The burst was recorded on 7 June, 2011 in the frequency band 3--33~MHz. It was characterized by extremely rich fine structure. The statistical analysis of more than 300 herringbone sub-bursts constituting the burst was performed separately for the positively (reverse) and negatively (forward) drifting sub-bursts. The sense and the degree of circular polarization of the herringbone sub-bursts were measured in the respectively wide frequency band (16--32~MHz). A second order fine frequency structure of the herringbone sub-bursts was firstly observed and processed. Using STEREO COR1 (A,B) and SOHO LASCO C2 images the direction and radial speed of the CME responsible for the studied type II burst were determined. The possible location of the type II burst source on the flank of the shock was found.