Associations between coronal mass ejections and metric type II bursts

Abstract

view Abstract Citations (118) References (20) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Associations between coronal mass ejections and metric type II bursts Sheeley, N. R., Jr. ; Howard, R. A. ; Michels, D. J. ; Robinson, R. D. ; Koomen, M. J. ; Stewart, R. T. Abstract A statistical comparison of metric type II bursts and coronal mass ejections (CMEs) during 1979-1982 was carried out. 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. 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. CMEs without metric type II bursts were divided equally into groups faster and slower than 455 km/s. The faster CMEs were associated with interplanetary shocks, some of which originated on the visible disk where metric type II bursts should have been observed if they had occurred. These results suggest that (1) shocks without CMEs have a relatively impulsive origin and may die out sooner than many shocks with CMEs which are piston driven, and (2) either some fast CMEs do not reach shock-producing super-Alfvenic speeds until they leave the lower corona where the metric emission originates, or these CMEs form shocks that are unable to excite type II emission in the lower corona. Publication: The Astrophysical Journal Pub Date: April 1984 DOI: 10.1086/161954 Bibcode: 1984ApJ...279..839S Keywords: Shock Waves; Solar Corona; Solar Flares; Solar Wind; Solar X-Rays; Stellar Mass Ejection; Type 2 Bursts; Histograms; Mach Number; Solar Limb; Very High Frequencies; Solar Physics full text sources ADS |