[Mods shown in picture] (for those of you too lazy to search for them yourselves…)
Plasma Gatling MK 2.6 by Ajumi: http://www.nexusmods.com/fallout4/mods/5534/?
Diranars Gorgeous Glowing Plasma for Ajumis Plasma Gatling V1-0: http://www.nexusmods.com/fallout4/mods/7945/?
(CaN) Crimes against Nature ADD-ON pony companions: http://www.nexusmods.com/fallout4/ajax/downloadfile?id=80603
Better Dials for Power Armor: http://www.nexusmods.com/fallout4/mods/10937/?
It’s a plasma gatling gun mod. The glow of the barrels is added by another mod. I don’t have either mod so I entirely forget which two they are.