Showing papers by "J. Lang published in 1990"

The interpretation of the spectral line intensities from the CHASE spectrometer on Spacelab 2

Abstract: In this paper we analyse the solar spectral intensities observed with the CHASE grazing incidence telescope and spectrometer flown on NASA's Spacelab 2 Mission in 1985. Our main purpose has been to investigate the sources of error that arise in the application of the differential emission measure technique used to analyse such data. We suggest methods by which these sources of error may be investigated.

On the dependence of solar flare X-ray spectral line intensity ratios of highly ionized sulfur, calcium, and iron on electron temperature, differential emission measure, and atomic physics

Abstract: This paper focuses on what can be learned about the emission measure distribution and certain atomic physics parameters from spectral lines of highly ionized ions of sulfur, calcium, and iron that appear in solar flare spectra. The particular lines chosen for analysis allow the electron temperature to be determined independently of the assumption of ionization equilibrium. An attempt is made to find emission measure models based on selected functional dependences of emission measure on temperature that reproduce the observed temperatures deduced from spectral line ratios as well as the relative intensities of resonance lines of different elements.