Explosive events in the solar atmosphere

Two examples of explosive events observed with SUMER in transition region s pectral lines are reported here; one detected in C IV 1548 Angstrom, in a r egion within the northern polar coronal hole, and the ether in O VI 1032 An gstrom, in an active region. The event measured in C IV lasted similar to 3 min and extended approximately a region of 8 are sec along the slit (N-S) and 8 are sec in the E-W direction. Velocities reached around 150 km s(-1) in the blue wing and 100 km s(-1) in the red wing. The active region events were more energetic and in total lasted similar to 6 min. At the point of maximum activity, a region of 8 are sec along the slit is covered by one ex plosive event located in the northern section of the observed region, while in the southern section we observe two events very closely located and ext ended over a maximum of 14 are sec along the slit. More precisely, in the n orthern section we have at least two consecutive events occurring in a shor t time interval (similar to 12 min) separated by similar to 3 are sec. In t he EW direction the raster length covered by each of these events was appro ximately 4 are sec. The explosive events seen in O VI showed a very complex structure of subsonic and supersonic velocity flows, both red-shifted and blue-shifted. The apparent maximum velocity reached in the blue wing was ap proximately 250 km s(-1) and 215 km s(-1) in the red wing.