Abstract:
The corona is the outer most atmosphere of the Sun, overlying the photosphere and the chromosphere.
It extends to several millions of kilometers into space and is about 106
times fainter compared to the
photosphere. At optical wavelengths, it is observed primarily during a total solar eclipse. The solar
corona is also observable with coronagraphs wherein the bright light from the photosphere is occulted
artificially. Outside the optical window, the solar corona is also observable at radio and Xray
wavelengths. Observations of the solar corona at Xray
wavelengths are carried out from space since
the Earth's atmosphere doesn't allow the Xrays
from the outer space to pass through it. The primary
advantage of radio astronomy in observing the solar corona is that the observations can be carried out
from the ground as compared to the optical and Xray
wavelengths. Depending on the frequency of
observation, one can image different altitude levels in the solar atmosphere. Also it is possible to
observe polarized radio emission from the solar corona with a simple observing setup
and derive the
magnetic field there, as compared to other wavelengths.
In this project, a Cross polarized Log Periodic Dipole Antenna (CLPD) has been designed, where 0o
and 90o oriented arms are mounted on the same axis. The receiver system is used for both orientations
is same to minimize the instrumental errors. Using the correlation interferometry technique,
observations of the Sun and the calibrator sources are carried out to test the performance of CLPD.
