Relation between coronal type II bursts, associated flares and CMEs

TL;DR

This study analyzes complex solar events involving coronal type II bursts, flares, and CMEs, identifying two main groups with different shock origins, enhancing understanding of their interrelations.

Contribution

It classifies events into two groups based on the origin of type II shocks, clarifying the relationship between flares, CMEs, and radio bursts.

Findings

Type II shocks are either flare blast waves or CME-driven.

Two distinct event groups with different shock origins identified.

Radio burst characteristics correlate with flare and CME properties.

Abstract

We study a sample of complex events; each includes a coronal type II burst, accompanied by a GOES SXR flare and LASCO CME. The radio bursts were recorded by the ARTEMIS-IV radio spectrograph (100-650 MHz range); the GOES SXR flares and SOHO/LASCO CMEs, were obtained from the Solar Geophysical Data (SGD) and the LASCO lists respectively. The radio burst-flare-CME characteristics were compared and two groups of events with similar behavior were isolated. In the first the type II shock exciter appears to be a flare blast wave propagating in the wake of a CME. In the second the type II burst appears CME initiated though it is not always clear if it is driven by the bow or the flanks of the CME or if it is a reconnection shock.