Crystal spectrometry of active regions on the Sun

Abstract

A crystal spectrometer has been flown on a sounding rocket to study the soft X-ray line emission from the sun. Collimators, with a field of view 9 arc min square, allowed individual active regions to be observed. A detailed description of the instrument is given. Solar conditions at the time of launch are then discussed, together with a brief history of the three active regions studied. It is shown that the collimators performed satisfactorily. The spectrum of an active region is used to identify the important solar line emission, and a comparison of the spectra obtained near 1.7 nm is made. The temperatures of the regions are discussed, and it is shown that a non-isothermal model is required. A good correlation is found between the soft X-ray emission and other solar observations.