SOLAR GAMMA-RAY-LINE FLARES, TYPE-II RADIO-BURSTS, AND CORONAL MASS EJECTIONS

We use a Big Flare Syndrome (BFS) test to substantiate earlier reports of a statistically significant association between nuclear gamma-ray-line (GRL) flares (observed by the Gamma Ray Spectrometer on the Solar Maximum Mission) and metric type II bursts from coronal shocks. The type II onset characteristically follows the onset of gamma-ray emission with a median delay of 2 minutes. We find that 70%-90% of GRL flares for which coronagraph data were available were associated with coronal mass ejections (CMEs). Gradual and impulsive GRL flares were equally well associated with CMEs. The CMEs were typically fast, with a median speed greater than 800 km s-1. We discuss the following possible "non-BFS" explanations for the GRL-type II association: (1) the "type II shock" accelerates GRL protons in a "second step" process as it traverses lowlying coronal loops, (2) the observed shocks are blast waves resulting from the sudden deposition of energy in the low corona signaled by the GRL event, and (3) a fast CME is the underlying independent cause of both GRL and type II emission from GRL flares.