Do coilguns or railguns make more sense for exoatmospheric CIWS?
Does either make sense for an anti ship weapon?

The problem with coilguns is that of computer timing the rings on time.
Which we have the means to do.
And energy, but just strap a nuclear reactor to it.
Rialguns have a problem with barrel life.
That said nuclear battleship would be so cool

>>64029400 (OP)
Coilguns lack range, rail guns lack durability.
Coil guns are basically useless for any application because traditional cannons are better in every way.
Rail guns are basically useless because missiles can do the same thing.
In order to have a railgun you'll need about a quarter of the size of a ship in just capacitors and about half of the ship's power to recharge them.

>>64029439
>Coilguns lack range,
In an exoatmospheric setting? Why?
>because traditional cannons are better in every way.
If you have to carry the propellant in space that seems like a gigantic downside

>>64029400 (OP)
Small rail large coil

Which is more advantageous in the case of electric heating and cooling?

OP is a retard as usual, but coilguns aren't ideal for gun:

Coil launcher:
1. Contactless/brusheless and more freedom of size. One problem is the need of a highly magnetic projectile, a shell, warhead is ok as long as it doesn't overheat or the fuze is compatible with the EM field.
2. For guns with barrels of restricted lenght, the practical muzzle velocity is limited to 200-500 m/s.
3. Coil launchers are just a variant of linear motors and they're usually are proposed for things like lunar launchers with multi-km "tubes". For that situation they can make sense because brusheless removes a lot of problems

Rail launcher:
1. They kinda work up to 2.5-3 km/s with current tech. The problem is that in the end they aren't far better than a hypervelocity gun using normal propellant. The projectile yawing has been is problematic in all big railgun tested.
2. Beyond 3 km/s to 4 km/s capacitors, rails are a problem because railguns simply don't scale well, the peak power required increase by at least the cube of speed V^3, and more power means more current so all the mechanical stress induced by the magnetic field is far worse. This is unrelated to contact wear.
3. Even if you don't need a magnetic projectile like coilguns the weight of the sabot is similar to the weight of the projectile in tested railguns (by comparison tank guns the projectile is 60-80% of the moving mass), that means ~50% of the kinetic energy is useless.

>>64029400 (OP)
Plasma weaponry makes the most sense, but God speed getting the necessary forms of physics declassified inorder to create an effective one.
Maybe one day