X-Radiation (E> 10 keV), H𝛼 and Microwave Emission During the Impulsive Phase of Solar Flares

Vorpahl, Joan A., X-Radiation (E> 10 keV), H𝛼 and Microwave Emission During the Impulsive Phase of Solar Flares, Sol. Phys., 26, 397-413 (1972) (ADS)

The cartoon

(click on the image for a larger version)

Ah, 1972! Relatively early in our Archive, Joan Vorpahl produced this nice depiction of the joint variation of hard X-rays, microwaves, and Hrα emissions. The standard impulsive-phase cartoon continued like this, while the CSHKP versions would generally just add a cusp structure at the loop top. Note this cartoon's laconic omission of magnetic reconnection and its focus on flare phenomena, as opposed to CMEs. The suggestions that the Hα flare emission ("the chromosphere") rises above 12 Mm, and does so preferentially on the following side of the active region, may not have been fully borne out in later work. Regarding the heights, we know much more now about the third dimension in the solar atmosphere, but it would be interesting to gain some direct information about the physical heights of the across the line profile of the Hα (or Lyα) emission. The footpoints of the "hard electrons" are now known to occur very deep in the atmosphere, because of their congruence with the white-light flare emission.

Date: 2012 February 14

Update: 2019 December 04