Energetic interplanetary shocks, radio emission, and coronal mass ejections

Abstract

The interplanetary shocks which generate detectable low‐frequency (< 1 MHz) radio emission, represent as a group, the most energetic shocks produced by the sun. For all interplanetary (IP) shocks which generated so‐called IP type II events, we find, when observations were available, that the associated solar events involved fast (>500 km/s) coronal mass ejections (CMEs). In comparison with the set of all CMEs detected by the Solwind coronagraph, the CMEs associated with IP type II events are the most massive and energetic. The majority (>50%) belong to the structural classes described by the Solwind researchers as “curved front” or “halo.” Evidence presented suggests that these are the same class viewed from a different perspective. Our results are consistent with there being a close relationship between interplanetary shocks and fast CMEs.