Radio signatures of CME-streamer interaction and source diagnostics of type II radio burst

TL;DR

This paper presents a method combining radio and white light observations to locate electron acceleration sites in solar eruptions, demonstrated through analysis of a 2003 event with spectral bumps indicating shock-streamer interactions.

Contribution

It introduces a novel approach linking spectral features of type II radio bursts with imaging data to infer acceleration locations during CMEs.

Findings

Spectral bumps correlate with CME entering streamer regions.

Analysis of 2003 November 1 event supports the method.

Provides a new diagnostic tool for shock-related electron acceleration.

Abstract

It has been suggested that type II radio bursts are due to energetic electrons accelerated at coronal shocks. Radio observations, however, have poor or no spatial resolutions to pinpoint the exact acceleration locations of these electrons. In this paper, we discuss a promising approach to infer the electron acceleration location by combining radio and white light observations. The key assumption is to relate specific morphological features (e.g. spectral bumps) of the dynamic spectra of type II radio bursts, to imaging features (e.g. CME going into a streamer) along the CME (and its driven shock) propagation. In this study, we examine the CME-streamer interaction for the solar eruption dated on 2003 November 1. The presence of spectral bump in the relevant type II radio burst is identified, which is interpreted as a natural result of the shock-radio emitting region entering the dense streamer structure. The study is useful for further determinations of the location of type II radio burst and the associated electron acceleration by CME-driven shock.