Questions regarding the papers by David et al. and Hassler et al. Note: These are not assigments, just items to ponder while reading the papers, and issues to discuss in the class. Don't feel inadequate if you cannot answer them on your own! Hassler et al. 1. Explain the overlapping of first and second order spectra. Any idea how this comes about? 2. Some quick number checking: with a pressure of about 0.2 dyne/cm^2 at the base of cornal holes (Dupree, 1972), and the Ne VIII radial outflow velocities as measured, what is the surface filling factor of the network for a mass loss of about 10^(-14) solar masses per year? (Use the Ne VIII formation temperature from the paper). How does that compare with the perceived areas with blueshifts? 3. What's the problem with the map of the blue-shifts in the polar coronal hole (fig. 6)? David et al. 1. Is the straylight contamination that much better than, say, SXT? 2. The missed opportunity: Look at the curves in Fig. 2. Measure dln(I)/dr in the linear part of one curve. What does that mean? OK, here we go: use the gas law and momentum conservation to calculate dln(rho)/dr, which gives you a measure of what? What is the relation between intensity I and density rho? So what can we calculate from the observed dln(I)/dr? And what is the physical interpretation? 3. What do you think of the following statement in the Discussion, "These lines are formed primarily in the solar corona, so that instrumental scattering from the disk is not important, and has not been removed". If you can explain it, please enlighten me!