EUV Sprays: Jet-like eruptive activity on the solar limb

Jet-like eruptive events have been detected in the extreme ultraviolet (EUV ) observations from the Solar and Heliospheric Observatory (SOHO) spacecraf t. Some jet-like events are shown and for one event, that of January 22 200 0, we provide a detailed analysis of the EUV observations. The January 22 o bservation was part of an on-going campaign to observe the onset of coronal mass ejections (CMEs) using extreme ultraviolet spectroscopy. A high-tempe rature fan-like jet was first detected in emission lines from plasmas at on e million K and over, and it appears to be the onset of a narrow mass eject ion identified later in coronagraph data. This was followed by a dramatic j et or finger of cool (less than or equal to 250 000 K), rotating plasma whi ch extended vertically, high into the corona. It extended well beyond the f ield of view of the instrument and appears to relate to a small ejected clo ud which is detected in subsequent coronagraph data. The spectroscopic char acteristics are used to provide plasma diagnostic information for these two events, and this combined with images for a wide range of temperatures all ows a thorough investigation of the processes leading to such eruptions. A simple accreting magnetic field model is used to descibe the basic features of the jet activity.