X-ray jets and X-ray plasmoids

The soft X-ray telescope (SXT) aboard Yohkoh has discovered coronal X-P ay jets associated with small flares (microflares - subflares). It has also discovered X-ray plasmoids not only from large LDE flares but also from compact impulsive flares. X-ray jets are well collimated hot plasma ejections, while X-ray plasmoids are blob-like hot plasma ejections (sometimes seen as loop-like ejections in three dimensional view). Nevertheless, the velocity of both hot plasma ejections is similar, of order of a few 100 km/s on average. The observational characteristics of these newly discovered hot plasma ejections are reviewed, and a unified model based on magnetic reconnection mechanism is presented to account for these apparently different mass ejections.