This is a Cycles shader for the likes of Lazers, Energy beams, or even for a Still Explosion effect.
It uses 2.78's adaptive subsurf, so you will need to set your render support to "experimental" and apply a subsurf modifier, with "Adaptive" selected.
Very nice! I put everything after the color ramp into a group (so I could still adjust the color, but everything else was hidden away) and saved it in my default file!
Thanks for this, it looks great!
Cool dude!
Cheers, Rex