Click on the image above for a larger version.
One of the founding cartoons of flare theory. Giovanelli's ideas went on to inspire not only the MHD-based theoretical work (e.g., Dungey; Gold & Hoyle; Cowling; Sweet; Parker and many others) but also theoretical work based upon electrical discharge, ie plasma physics requiring kinetic descriptions. This cartoon shows magnetic field lines emanating from "spots", the circles lying in the photospheric plane, plus currents (dashed lines) linking neutral points and flowing in sheets. I find this a little hard to understand! Note though that one sees the geometrical paraphernalia of 3D reconnection: separators, separatrices, spines and fans, much as in cartoons done generations later (e.g., the Bratenahl-Baum cartoon of 1976, or the Fletcher et al. cartoon of another quarter-century later).
Note that this cartoon was also published in Giovanelli's 1947 paper as well (MNRAS 107, 338).
July 2, 2006
December 30, 2006.
ADS citation rate 0.31 per year!
Why would such a far-seeing and influential piece of work have so few
modern citations?
September 3, 2007. Added the page title and admired the work again.
March 5, 2008