Properties of DH Type II Radio Bursts and Their Space Weather Implications

TL;DR

This study analyzes the properties of DH Type II radio bursts over two solar cycles, linking their characteristics to CME features and space weather impacts, especially in predicting solar energetic particle events.

Contribution

It provides a comprehensive analysis of DH Type II radio bursts, highlighting their association with CME properties and their potential as space weather indicators.

Findings

DH Type II bursts are linked to fast, wide CMEs, often halos.

About half of the bursts extend down to 0.5 MHz, indicating large heliocentric distances.

Western hemisphere bursts extending to lower frequencies predict solar energetic particle events.

Abstract

We report on the properties of type II radio bursts observed by the Radio and Plasma Wave Experiment (WAVES) on board the Wind spacecraft over the past two solar cycles. We confirm that the associated coronal mass ejections (CMEs) are fast and wide, more than half the CMEs being halos. About half of the type II bursts extend down to 0.5 MHz, corresponding to a heliocentric distance of tens of solar radii. The DH type II bursts are mostly confined to the active region belt and their occurrence rate follows the solar activity cycle. Type II burst occurring on the western hemisphere of the Sun and extending to lower frequencies are good indicators of a solar energetic particle event.