Observations of correlated white-light and extreme-ultraviolet jets from polar coronal holes

Time-lapse sequences of white-light images recorded with the Large Angle Sp ectrometric Coronagraph (LASCO) on the Solar and Heliospheric Observatory ( SOHO) frequently show long, narrow structures moving outward over the Sun's polar regions at high apparent speeds. By comparing the LASCO observations with Fe XII lambda 195 spectroheliograms made with the Extreme-ultraviolet Imaging Telescope (EIT) on SOHO between 1997 April and 1998 February, we h ave identified 27 correlated white-light and extreme-ultraviolet (EUV) jet events. In each case, the EUV jet was observed near the limb of the polar c oronal hole 20-60 minutes before the corresponding white-light jet was regi stered in the coronagraph's 2-6 R. held of view. The jets originate near fl aring EUV bright points and are presumably triggered by field line reconnec tion between magnetic bipoles and neighboring unipolar flux. The leading ed ges of the white-light jets propagate outward at speeds of 400-1100 km s(-1 ), whereas the bulk of their material travels at much lower velocities aver aging around 250 km s(-1) at heliocentric distances of 2.9-3.7 R.. These lo wer velocities may reflect the actual outflow speeds of the background pola r wind.