Schmieder, B., P. Heinzel, J. E. Wiik, J. Lemen, B. Anwar, P. Kotrc, and E. Hiei, Relation between Cool and Hot Post-Flare Loops of 26 June 1992 Derived from Optical and X-Ray (SXT-YOHKOH) Observations, Sol. Phys., 156, 337-361 (1995) (ADS)
(click on the image for a larger version)
Date: 2020 September 02
A rather primitive and confusing cartoon, but this was from an earlier time in the Universe. Here we see the standard picture embedded in the CSHKP model; hot loops (labeled "SXT" to note the Yohkoh observations) cool down to the Hα temperature range, and then disappear as "coronal rain" over a certain time scale. The Archivist comments that in this picture, a unique flux tube, if such a thing can be defined, cools monotonically as it loses pressure; then (the hatched region) the Field thermal instability sets in, the gas is suddenly overdense and underpressure, and it rains. The Archive has surprisingly few better representations of this very elementary physics, but the reader could check out the Martens-Kuin cartoon where it's part of the story.