Recent results on various aspects of solar energetic particles are reviewed. A possible grain component of the polar particles is discussed in brief. The plasma component namely the solar wind and the solar energetic ...

The spectroscopic techniques in the X- and EUV region to determine electron density and temperature of solar plasma have been presented. The line intensity ratios as a diagnostic probe of solar plasma from berrylium, boron, ...

Solar eclipses established the existence of the outer region of the solar atmosphere, the solar corona, extending to several solar-radii and exhibiting open and closed magnetic field patterns. The density and the temperature ...

Sun could have had a nice and perfect spherical symmetry in its atmosphere and probably no variations on time scales smaller than hundreds of thousands of years if (i) the energy produced in its core could be transported ...

The flow field in stellar convection zones, characterised by high Rayleigh number, low Prandtl number and large Reynolds number, is time dependent and turbulent, consisting of eddies having a range of scale-lengths upto ...

Many of the oscillations observed at the solar surface have been identified with resonant normal modes of the entire solar body. Accurate measurements of frequencies of these modes enable us to study the internal structure ...

A formal solution of equation transfer with aberration and advection terms is developed for spectral lines taking into consideration partial redistribution of photon in a spherical medium which is expanding with a radial ...

An infrared photometer system has been developed for photometry of astronomical sources in the spectral band 1 to 5 microns. The characteristics of the system and preliminary engineering tests using the 1- m optical ...

A null test for testing aspheric Schmidt corrector plate has been described. This paper gives a detailed procedure and a computer programe for computing optimum test parameters. A typical run of the program for testing a ...