Solar gamma-ray-line flares, type II radio bursts, and coronal mass ejections

A Big Flare Syndrome (BFS) test is used to substantiate earlier reports of a statistically significant association between nuclear gamma-ray-line (GRL) flares 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 two minutes. It is found that 70-90 percent 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. possible `non-BFS' explanations for the GRL-type II association are discussed.