a lot of that is 2d glows and gradients.
pulling up the colours in post so you get more blown out areas and blowing out the yellows (in the 2nd one) etc. plus overlaying patterns over the top etc.
just finding some good image sources to composite over the top as overlays, additives, lightens and multiplys will give you some intersting results, then playing with blurs, glows, contrast/brightness and opacity of the layers etc. is a good start. essentially this is all photoshop stuff that you do afterwards 
just build some nice particle elements with variation in colour (particle age etc) maybe apply glow there or else in 2D gives you the starting point to go from, although this is all design stuff rather than particle specific effects.
PS. check 3dluvr I’m sure I’ve done a tut or two on ab combustion, that kind of stuff will create nice nebulas which work well when glowing etc.