NEAR-SIMULTANEOUS OBSERVATIONS OF X-RAY PLASMA EJECTION, CORONAL MASS EJECTION, AND TYPE II RADIO BURST

Abstract

We report the first simultaneous observation of X-ray plasma ejection (XPE), coronal mass ejection (CME), and type II solar radio burst on 1999 October 26. First, an XPE was observed from 21:12 UT to 21:24 UT in the Yohkoh SXT field of view (1.1 to 1.4 R ☉). The XPE was accelerated with a speed range from 190 to 410 km s–1 and its average speed is about 290 km s–1. Second, the associated CME was observed by the Mauna Loa Mk4 coronameter (1.1-2.8 R ☉) from 21:16 UT. The CME front was clearly identified at 21:26 UT and propagated with a deceleration of about –110 m s–2. Its average speed is about 360 km s–1. At the type II burst start time (21:25 UT), the height of the CME front is around 1.7 R ☉ and its speed is about 470 km s–1. Third, a type II solar radio burst was observed from 21:25 UT to 21:43 UT by the Culgoora solar radio spectrograph. The burst shows three emission patches during this observing period and the emission heights of the burst are estimated to be about 1.3 R ☉ (21:25 UT), 1.4 R ☉ (21:30 UT), and 1.8 R ☉ (21:40 UT). By comparing these three phenomena, we find that: (1) kinematically, while the XPE shows acceleration, the associated CME front shows deceleration; (2) there is an obvious height difference (0.3 R ☉) between the CME front and the XPE front around 21:24 UT and the formation height of the type II burst is close to the trajectory extrapolated from the XPE front; (3) both speeds of the XPE and the CME are comparable with each other around the starting time of the type II burst. Considering the formation height and the speed of the type II burst, we suggest that its first emission is due to the coronal shock generated by the XPE and the other two emissions are driven by the CME flank interacting with the high-density streamer.