“…As will be seen, the method depends critically upon the similarity of the response functions to geomagnetic activity as described by Mendillo and Lynch (1979). Figure 14, taken from Mendillo and Lynch (1979), shows the geomagnetically quiet (QQ-days) and geomagnetically disturbed (DD-days) behavior of F-region variability; we shall refer to this as "geomagnetic ordering". The ?…”