Abstract:
In order to understand the nature of dynamics over an active
region (AR) , it is necessary to study the velocity and magnetic fields simultaneously.
We present the preliminary results from our analysis of spectropolarimetric
observations of active region NOAA-8426 over two days. These
observations were done using Advanced Stokes Polarimeter (ASP) instrument
of HAO-NSO (Elmore et al. 1992, Lites 1996) with the Richard Dunn Vacuum
Tower Telescope, USA. The line-of-sight (LOS) magnetic field information is
derived using least squares fitting of the Stokes-V profiles, in a weak field approximation.
Simultaneous LOS velocity information over these AR is obtained
in two ways: (i) Zero-crossing (ZC) velocities using Stokes-V profiles, and (li)
centre of gravity (COG) velocities using Stokes-I profiles. The former corresponds
to the magnetised plasma whereas the latter to the gross plasma over
the AR. Average relative velocities of isolated polarity regions of the AR are
presented in this paper.
