EUV line diagnostics for solar plasma

Abstract

We present the solar EUV wavelength region which is rich in emission lines from the upper chromosphere, transition region and the corona (10 to the power 4 < Te < 10 to the power 6 K). Spectroscopic diagnostic techniques have been used extensively to determine the physical conditions in the solar atmosphere for such diverse phenomena as coronal holes, active regions, sunspots, flares etc. In view of the Coronal Diagnostic Spectrometer (CDS) and the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) aboard and Solar and Heliospheric Observatory (SOHO), and extensive theoretical investigation of most of the abundant solar ions has been carried out in the spectral range 150 - 1610 Å which is covered by these two major instruments with excellent spectral, spatial and temporal resolutions. A few significant findings of this Ph. D. research form the basis of some important observing sequences by the CDS and the SUMER science teams.