Abstract:
Generally it has been considered that the plages and sunspots are the main contributors
to the solar irradiance. There are small scale structures on the sun with intermediate
magnetic fields that could also contribute to the solar irradiance. It has not yet been
quantified how much of these small scale structures contribute to the solar irradiance and
how much it varies over the solar cycle. In this paper, we used Ca II K images obtained
from the telescope installed at Kodaikanal observatory. We report a method to separate
the network elements from the background structure and plage regions. We compute the
changes in the network element area index during the minimum phase of solar cycle and
part of the ascending phase of cycle 24. The measured area occupied by the network elements
is about 30% and plages less than 1% of the solar disk during the observation
period from February 2008 -2011. During the extended period of minimum activity it is
observed that the network element area index decreases by about 7%compared to the area
occupied by the network elements in 2008. A long term study of network element area
index is required to understand the variations over the solar cycle.
