I'd seen that sort of effect in a couple of renders (e.g. Lenny2's "Jewel" and the 'no postwork comment convinced me it had been done using atmosphere). My own attempt ("Will O'The Wisp" - mild nudity warning)  fell a bit short of the mark and needed postwork. Your last picture above is exactly what I wanted... but in green/yellow.  Thanks for the information on how you did it (using the edge blend seems a great touch!) - I need to fish out the scene file and try using your settings.  :)

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The 3Dcheapskate* occasionally posts sensible stuff. Usually by accident.
And it usually uses Poser 11, with units set to inches. Except when it's using Poser 6 or PP2014, or when its units are set to PNU.

*also available in ShareCG, DAZ, and HiveWire3D flavours (the DeviantArt and CGBytes flavour have been discontinued).