THE OBSERVATION OF AN UNUSUALLY FAST TYPE-IV PLASMOID

We report the observation of a moving type IV burst of the "isolated source" variety with an unusually high plane-of-sky speed of 1600 km s-1 which amounts to ∼2800 km s-1 if radial motion is assumed. In the past "advancing front" type IV sources have been observed to have large speeds, due to their association with shock waves. The isolated moving type IV sources are believed to be associated with plasmoids and are generally slower: the fastest one previously reported had a plane of sky speed of only 880 km s-1. We discuss the consequences of the unusually fast motion of the plasmoid, such as shock formation and particle acceleration.