HIDA domeless solar telescope and SOHO coronal diagnostic spectrometer observations of short-duration active region blinkers.: II.: Extreme-ultraviolet properties

In a recent article, we reported the first detection of an Halpha counterpart to the EUV blinker in observations obtained by the Hida Observatory Domeless Solar Telescope (DST) and the SOHO Coronal Diagnostic Spectrometer (CDS). Using high-cadence, long-duration observations with CDS alone, we also confirmed the result of previous authors that EUV blinkers are in fact composed of short-duration (2-3 minutes), small (2"-3") brightening events. We suggested the name "elementary blinker'' and found that the Halpha counterparts closely resembled these events. This paper is the second part of a series that aims to firmly establish the properties of these elementary blinkers and their Halpha counterparts and thus to help understand the connection and relationships between different active phenomena in the solar chromosphere, transition region, and corona. In this paper, we perform a statistical study of the EUV properties of active region elementary blinkers and examine correlations between the various observed quantities. We also discuss the results and their relevance to uncovering the physical mechanism responsible for blinkers. Among the most significant results, we find 1. an increase in the number of events with decreasing duration; 2. typical intensity increases in the He I 584 Angstrom and O V 629.7 Angstrom lines of a factor in the range 1.1-1.7 and 1.1-2.73, respectively; 3. the majority of events that show significant relative Doppler velocities and width changes in He I 584 Angstrom and O V 629.7 Angstrom show redshifts and line broadening, in agreement with previous works on longer duration events; 4. there is a strong positive correlation between the relative velocities in He I and O V; 5. there is a strong positive correlation between the relative line widths in He I and O V; 6. there are weak positive correlations between the intensity increases during the events and the relative line widths for He I and O V; 7. there is essentially no correlation between the intensity increases during the events and the relative velocities for either He I or O V; 8. the peak intensity in the lower coronal line (Mg IX 368 Angstrom) correlates better with the peak intensity in the chromospheric line (He I) than with that in the transition region line (O V), whereas the chromospheric (He I) and transition region (O V) intensity increases correlate better with each other than with that of the coronal line (Mg IX). We interpret this last result as evidence that the transition region is primarily decoupled from the chromosphere and corona (in support of the unresolved fine structure view), since the intensity increases are dominated by the blinker, whereas the peak intensities retain a significant contribution from the steady quiet-Sun emission. If correct, this result also implies that elementary blinkers are not responsible (at least not directly) for the steady coronal heating, since the behavior of the correlations seems to be quite different from that of the quiet-Sun atmosphere.