The only point to researching them is to essentially have larger infrared lasers for fewer tech points, which is... not great, because you're essentially forsaking every other laser technology role in the process.
This is actually a
huge benefit to plasma carronades, because that "fewer tech points" part is actually a massive difference bordering on order of magnitude.
For example, a base-tech plasma carronade:
Off-Topic: 15 cm C1 Plasma Carronade • show
Damage Output 6 Rate of Fire 30 seconds
Max Range 60,000 km Carronade Size 4 HS (200 tons) Carronade HTK 2
Power Requirement 6 Recharge Rate 1
Cost 2.4 Crew 8
Development Cost 109 RP
Materials Required
Duranium 0.5
Corundium 1.4
Boronide 0.5
This can be built out of the box on a TN start (500 RP after TN Tech on a conventional start) for a very low 109 RP component research cost.
By contrast a 15 cm infrared laser:
Off-Topic: 10.0cm C1 Infrared Laser • show
Damage Output 6 Rate of Fire 30 seconds Range Modifier 10,000
Max Range 60,000 km Laser Size 5 HS (250 tons) Laser HTK 2
Power Requirement 6 Recharge Rate 1
Cost 2.4 Crew 15
Development Cost 109 RP
Materials Required
Duranium 0.5
Boronide 0.5
Corundium 1.4
has the same development cost but requires 6000 RP (7000 on a conventional start) to develop the same capability.
Okay, but that's early game tech which doesn't matter that much, even on a conventional start it isn't hard to invest a couple years and a few dozen labs to get something shiny. What about later in the game? Well, for a total of 30k RP (i.e., 15k RP for the last tech) we can have a 40 cm carronade:
Off-Topic: 40 cm C1 Plasma Carronade • show
Damage Output 40 Rate of Fire 200 seconds
Max Range 400,000 km Carronade Size 12 HS (600 tons) Carronade HTK 6
Power Requirement 40 Recharge Rate 1
Cost 6.3 Crew 24
Development Cost 177 RP
Materials Required
Duranium 1.3
Corundium 3.8
Boronide 1.3
For 30k RP that actually looks pretty nice, but what about lasers? Well, for 30k RP we can either have this not nearly so impressive-looking 25 cm laser:
Off-Topic: 25.0cm C1 Infrared Laser • show
Damage Output 16 Rate of Fire 80 seconds Range Modifier 10,000
Max Range 160,000 km Laser Size 8 HS (400 tons) Laser HTK 4
Power Requirement 16 Recharge Rate 1
Cost 4 Crew 24
Development Cost 141 RP
Materials Required
Duranium 0.8
Boronide 0.8
Corundium 2.4
...ugh. Or, we could split our research between caliber and wavelength techs, as
God Steve intended, and deploy something like this:
Off-Topic: 20.0cm C1 Ultraviolet Laser • show
Damage Output 10 Rate of Fire 50 seconds Range Modifier 40,000
Max Range 400,000 km Laser Size 6 HS (300 tons) Laser HTK 3
Power Requirement 10 Recharge Rate 1
Cost 12.6 Crew 18
Development Cost 250 RP
Materials Required
Duranium 2.5
Boronide 2.5
Corundium 7.6
That looks a lot better. The alpha damage is a lot less, but it's half the size and fires 4x faster at the same maximum range (so probably limited by BFC tech at this point in the tech tree). It is however more expensive (~2x the cost per weapon, ~4x the cost per ton), and of course with such low alpha damage for lasers the "plasma bomber" approach still runs a good chance of decimating a fleet if a close-range ambush can be pulled off, such as when defending against a JP assault which conveniently enough is one of the main use cases for plasma.
It is worth pointing out that if we want to deploy a 40cm laser, the required RP investment in caliber tech only would be 245k RP, a factor of eight times more RP than to deploy a 40cm plasma carronade. Again, the RP difference is an order of magnitude difference and is not a negligible consideration.
This RP-cheap nature also makes plasma carronades a very effective research target for boosting the ground forces racial attack level, as for the same nominal RP investment one gains an additional level of racial attack (and compared to lasers one can even pull two levels ahead since lasers and other weapons require multiple tech lines, although in practice this doesn't always happen due to concurrent investment in missiles or Gauss PD techs). This is another significant consideration when considering how well plasma carronades are balanced from the broader strategic perspective.
Overall I find plasma weapons to be fairly well-balanced, and I like using them as a backup beam weapon in missile-heavy fleets when I do not want to expend a lot of RP into lasers or particle beams at the expense of my missile, sensor, and PD techs. To be clear, for a primary beam weapon I will prefer lasers, railguns, or particle beams every time, but for a secondary or tertiary weapon plasma works well and has its own advantages so in my view it is quite usable. I think the mistake many players make is that the compare plasma to lasers on the premise that all beam weapon types should be equally viable and "balanced" as a primary fleet armament, which simply is not how Aurora
is balanced nor should it be. It is entirely okay for some beam weapon types to be narrow and specialized, as long as they still have a useful niche in the game I think "balance" is achieved. Thus in my view, plasma is balanced in the same manner as HPMs and Gauss cannons as a viable secondary weapon (mesons, however, I have yet to find a compelling argument or use case for and I maintain they have been over-nerfed due to their power in VB6).
