Associations between coronal mass ejections and metric type II bursts

A statistical comparison of metric type II bursts and coronal mass ejections (CMEs) during 1979--1982 revealed the following principal results: 1. Type II bursts without CMEs were associated with short-lived (0.5 hr) soft X-ray events, but not with interplanetary shocks at the Helios 1 spacecraft. 2. Type II bursts with CMEs were associated with longer-lived X-ray events (3 hr on the average) and interplanetary shocks, and the CMEs had speeds greater than 400 km s-1. 3. CMEs without metric type II bursts were divided equally into groups faster and slower than 455 km s-1. The faster CMEs were associated with interplantary shocks, some of which originated on the visible disk where metric type II bursts should have been observed if they had occurred