| I define and describe the dominant emission mechanisms and astronomical sources seen in the extreme ultraviolet. In chapter 2, I review the operational characteristics of microchannel plates (MCPs) used in EUV imaging detectors. I then discuss the design, construction and performance of the wedge, strip and zig imaging microchannel plate detectors built for the ALEXIS (Array of Low Energy X-ray Imaging Sensors) satellite. In the following chapter, a theory describing the behavior of EUV photocathode materials is developed and applied to ALEXIS calibration data.;In the second section of the thesis I review the theories and observations of solar and late type star coronae, followed by a overview of solar and stellar flare physics. In chapter 6, I describe and analyze the EUVE (Extreme Ultraviolet Explorer) Deep Survey (65-190 A) lightcurve of a large flare seen on the dMe flare star, AU Microscopii 15 July, 1993 lasting 1.5 days with a peak volume emission measure of 10;I then discuss an EUVE observation of the dMe flare star AD Leonis. Two small flares there observed in the optical and by EUVE on 1-3 March 1993. The flares were visible for roughly 22 and 2 hours respectively with volume emission measures of 2 ;I conclude with a short discussion attempting to reconcile the reported 10... |
