Abstract:
The synoptic observations of Kodaikanal form one of the
longest unbroken solar data from the beginning of the 20th century to the
present day, and consists of the white light and monochromatic images of
the sun. In this review, I shall discuss the results of the investigations in
two areas using these data: (i) Tilt angles of the magnetic axes of bipolar
spot groups, and (ii) structure and dynamics of large scale unipolar
magnetic regions on the solar surface.
The observed properties and patterns of behaviour of the tilt angles can
be used as effective diagnostics to infer the physical conditions in the
subsurface layers of the sun, and thus get an insight into the physical
effects that act on the rising magnetic flux tubes during their journey
through the convection zone to the surface.
The second topic of discussion here, namely, the studies of the dynamics
of unipolar regions over several solar cycles, show that the global solar
activity has a high latitude component which manifests in the form of
polar faculae, in addition to the well known sunspot activity at the middle
and low latitudes. This raises the question about the origin of this high
latitude component.
