Neidig, Donald F., Zdenek ŠvestkA, Edward W. Cliver, Vladimir Airapetian, and Timothy W. Henry, Observations of Faint, Outlying Loop Systems in Large Flares, Sol. Phys., 170, 321-339 (1997) (ADS)
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Date: 2009 May 05
Update: 2019 November 26
Deviating from CSHKP to explain "flare nimbus", perhaps with perhaps a record-setting number of 2D complexities. The large-scale structures seen in early Hα observations were described in terms such as "nimbus", "flash", "cloud"; please read this paper for a connection to these historical things. A good further contribution here is the recent McKenna-Lawlor cartoon.
We should not belittle the Hα flare observers, because they became us!