fl232.gopalswamy05 Posted: 26-Apr-96 Updated: 27-Jan-97 Events specified: See Text
N. Gopalswamy and M. R. Kundu (Univ of Maryland)
P. K. Manoharan, M. Pick and P. Zarka (Meudon)
H. Hudson, N. Nitta (SXT)
In principle, both flares and CMEs can produce MHD shocks. Type II radio bursts in the metric frequency regime are believed to be signatures of coronal shock waves. Past imaging observations of type II bursts using Culgoora and Clark Lake radioheliographs have supported the view that the coronal shocks are produced by flare explosions, rather than by CME pistons. In the past observations, there were no good imaging observations of X-ray flares made simultaneously with type II bursts and hence we could not fully undersand the spatial characteristics of flares and type II bursts. The Yohkoh/SXT is well suited for such a study and we propose to investigate some specific events. We shall look for mass motions, structural changes and plasmoid ejections associated with the type II bursts.
>From the Nancay Decametric Array observations and the quick look data of Nancay radioheliograph, we have identified the following events with overlapping observations with Yohkoh/SXT.
Date Strt End (UT)
30 apr 93 14:26 14:33 27 jun 93 11:32 11:46 22 jul 93 08:57 09:16 07 jul 94 10:00 10:24 12 jul 94 09:19 09:41 31 jul 94 10:29 10:50We have done preliminary analysis of the SXT data for the 1993 April 30 and 1994 Jul 31 data. In both cases there are dynamical phenimena associated with the type II bursts. We are in the process of analyzing the remaining events.
Update 27-Jan-97
We have completed the analysis of two events in the list: Jul 31 1994 and april 30 1993. The former is a disconnected plasmoid/CME event associated with type II and type IV radio bursts. We are about to submit a paper for publication. We will mail you the abstract of the paper. The second event is a dynamic/thermic DB event again with a type II and type IV. We are in the process of preparing the research report for publication. Once these two are completed, we will go down the list for other events.