Jagdev Singh
Indian Institute of Astrophysics, Bengaluru

The plasma in the solar corona is dynamic, inhomogeneous, and very hot at about million of degrees. It has many features such as prominences, coronal loops, polar plumes, streamers, solar flares and CME's. It is still debateable how the plasma in solar corona gets heated up to million degrees in short distance of about 5000 Km from the surface temperature of the sun , 5700 degrees?

The occurrence of total solar eclipse provide observations of solar corona with minimum of scattered light in the visible part and near IR of the spectrum but for short durations to study the intensity oscillations in the solar corona and the coronal magnetic fields. The varying sky transparency and scattered light introduces large amount of uncertainty when studying the high frequency oscillations and thus it becomes difficult to believe the results because of the low amplitude of the variations in intensity probably caused by coronal waves, have large uncertainties. Therefore a coronagraph with these instruments in space, above the earth’s atmosphere will provide ideal conditions to study the existence of waves. Keeping in view of the above mentioned facts we have proposed a 20 cm coronagraph to be launched in space by ISRO and take the images of the solar corona in the green (at 530.3 nm), red (637.4nm) emission lines and continuum with the view to understand the heating of solar plasma, formation of coronal loops, acceleration of CME's.

In this colloquium, I shall talk about, physical and dynamical characteristics of various coronal features, coronal observations and role of various physical processes in heating of the coronal plasma.