CORRELATION TRACKING TECHNIQUE FOR MEASUREMENT OF TRANSVERSE CHROMOSPHERIC MOTIONS

Local Correlation Tracking has been applied to line center H alpha fil tergrams for studies of transverse velocities in the chromosphere. It is found that the small-scale intensity structure of H alpha line wing images is strongly influenced by Doppler shifts, which gives rise to false signals of transverse motion that completely overshadow true tra nsverse velocities. On the other hand, this cross-talk effect is shown to be negligible in H alpha line center. The measured persistent tran sverse velocities in chromosphere (H alpha line center) and photospher e show a similar cell structure. It is concluded that the time average d transverse chromospheric velocities may not represent a net transpor t of mass. Time averaged H alpha line shifts give net redshifts corres ponding to regions of enhanced magnetic flux in the photosphere below.