Kinematic measurements of polar jets observed by the Large-Angle Spectrometric Coronagraph

We analyze polar jets observed by the Large-Angle Spectrometric Coronagraph (LASCO) instrument aboard the Solar and Heliospheric Observatory. The events studied here are from 1997 March 24 and August 5. The main objective of our analysis is to determine whether the jets' motions are consistent with ballistic behavior. Although ballistic trajectories have some-success in fitting the observed kinematic motions, there is substantial evidence that gravity alone is not regulating the movement of the jets. First of all, the August 5 events appear to exhibit slight accelerations rather than decelerations above 3 R.. Second, all the events studied here have very similar velocities, suggesting that by the time the jets reach the LASCO field of view, the jets have been incorporated into the ambient solar wind. If this is the case, the jets could be very useful as tracers of the solar wind at low heights in the Sun's polar regions.