SOHO Joint Operations Programme 91 ================================== CDS/TRACE - 18th May 1998 ------------------------- High Velocity Events in Polar Regions ------------------------------------- C.D. Pike, H.E. Mason & C.C. Kankelborg High velocity, dynamic events (macrospicules, jets etc) have been observed by CDS, frequently in the polar coronal hole regions (Pike and Harrison, 1998, Pike and Mason, 1998). These events are characterised by significant shifts in the spectral line profile of OV (2.5 x 10^5K). The CDS observations of dynamic events would complement the high cadence images from TRACE, by providing simultaneous data on velocities from Doppler shifted lines, which can be correlated with proper motions observed by TRACE. In addition, a number of spectral diagnostic lines formed at different temperatures through from 10^5 to 3 x 10^6 K, would provide the electron density and temperature distributions for these solar features. In this JOP, TRACE scans the polar region in a number of different filters over an area of around 4x4 arcmin^2. CDS would operate in a mode which scanned a 4'x4' area, searching for a dynamic event. When one is observed, CDS would be pointed in real time to observe a smaller area (1'x1') with a good cadence. CDS 1) Context raster (RT_MON, 4'x4', 42 mins) 2) Repeats of (RT_HVE, 1'x1', 10 mins) Duration: 4-5 hours TRACE Contact: Charles Kankelborg Suggested sequence(s): cck.southpolar.1x1.171 - only 171 images, 20 sec cadence, full fov