Timing and occurrence rate of X-ray plasma ejections

Publisher Summary This chapter discusses the occurrence rate of X-ray plasma ejections prior to the flare for various classes of solar flare. Yohkoh observations show that solar flares occur through magnetic reconnection above flare loops. It is expected from reconnection models that plasmoid ejections should be observed in all flares. X-ray plasma ejections are, however, found in only 35–40% of 128 flares from the C to X classes and in only 20–35% of 71 flares from the A to C classes. These results seem to be inconsistent with the expectation of the reconnection model. The chapter also examines the temporal relation between X-ray plasma ejections and flares using 126 limb flares. Experimental results indicate that the main X-ray plasmoids already start to rise before the peak of the hard X-ray (HXR) emission. The occurrence rate of X-ray plasma ejections was examined with the help of 57 flares. It is difficult to detect X-ray plasmoids in the weaker flares. Thus, it was proposed that X-ray plasma ejections are general phenomena associated with solar flares.