Kahler, S. W., R. D. Petrasso, and S. R. Kane, The quantitative properties of three soft X-ray flare kernels observed with the AS&E X-ray telescope on SKYLAB, Sol. Phys., 50, 179-196 (1976) (ADS)
(click on the image for a larger version)
Date: 2019 November 12
A very early flare cartoon based on soft X-ray imaging, in this case from the S-054 telescope on board Skylab [1]. Here the appeal is to an emerging flux region (EFR) as a trigger, pointing to a neutral sheet formed between the new flux and pre-existing flux. This is therefore a predecessor of the much-better-known Hevyaerts-Priest-Rust cartoon. It is also a predecessor to the Yohkoh descriptions of the so-called loop-loop flare scenario, which inspired the innovative Melrose alternative.
[1] Skylab