@Mentat you have been added, so you should be able to see the hidden tester's forum.
Plasma tech tree
Start with---->Plasma-F Plasma-G which leads to--->
Plasma R Torpedoes---> with rest of plasma tech tree----> Next Gen plasma Torps
Plasma-S Torps--->Plasma-D Torps--->Plasma-D Racks---> Starbase Plasma-D Racks
Minor Plasma Enhancements--->with 4th level ECCM->built in ECM--->Pseudo Torps--->Self Guiding Torps--->Destroyed Launch Tubes Launching---> Swivel Mounts
Minor Plasma Enhancements---Major Plasma Enhancements
Major Plasma Enhancements--->Plasma Shotgun--->Enveloping Torps--->Plasma Bolts
Plasma F & G; Ships can have either Plasma F or Plasma G, but not both till larger ships and refits are researched
Plasma G; G type torps can now be upgraded to Plasma S Torps
Plasma R; Ships using the Plasma R Torps are now available
Plasma D; Refit that increases a ships anti-air strength
Plasma D Rack; further upgrade to anti-air strength
Starbase Plasma D Racks; Starbase upgrade to anti-air strength.
Built in ECCM; Increase plasma using races attack strength.
Pseudo Torpedoes; Increase plasma using races attack strength.
Self-Guiding Torpedoes; Increase plasma using races attack strength.
Destroyed tube Launch; Increase plasma using races attack strength.
Swivel mounts; Increase plasma using races attack strength.
Plasma Shotgun; Increases anti-air strength
Enveloping Plasma Torpedoes; Largest increase to plasma users attack strength.
Plasma Bolts; small increase in attack strength
Next Gen Torps. I have no idea what to do after this.
NOTE: The 4th level of ECCM is ONLY required for the Built in ECCM for the trop, not the rest of that branch.
Cheers, Thorgrimm