Investigations of highly ionized atoms using fast ions and laser produced plasmas with astrophysical applications

Lifetime measurements using the beam-foil technique have been performed in He-like oxygen and fluorine, Be-like nitrogen and oxygen and Na-like sulphur and chlorine. Hyperfine induced decay of the 1s2p 3P0 level in F VIII has been observed. Accurate oscillator strengths of the 2s21S-2s2p 1P transition in N IV and O V and 3s2S-3P2sp(p) transition in S VI and Cl VII have been obtained. Spectropic studies in highly ionized F, S, C and the iron group elements from K to Ni using sparks, beam foil technique and laser produced plasmas have been undertaken. The spectra of Cl VII and Cl VIII have been studied in the wavelength region 100-6000 Aa. The Ne-like sp5 3s, 3p and 3d configurations have been studied up to Fe XVII. Along with these experimental studies ab initio relativistic calculations for isoelectronic comparisons have been performed. The 2p4 3s, 3p and 3d configurations have been analysed in S VIII, Cl IX and Ti XIV. Based on isoelectronic extrapolation identification of Fe XVII and Ni XIX in solar flares has been made. (author)