I am lucky enough to have the opportunity to play Armored Core, so I'll try to explain somethings not really releated, to kind:
In many movies, pulse cannon is a rapid-fire weapon (like a machine-gun).
Exactly, that's a Pulse Cannon, some weapon types are self explanatories, for example a tractor weapon, is a weapon that can move or pull you, there are no Tractor Beams implemented (maybe it can be done), at least if your ship either small or capital have Shield, more than pierced it should cause a Tractor effect that depends on Beam Size and power.....
Q: However, then why it's not a Machine-Gun ??
A: There are two Kind of weapons:
1- Ammunition (consumption)
2- Energy (consumption)
1- They have a quantity and are not infinity, physical bullets, not generated, but stored and launched (like FS2 Secondaries [Missiles]), normally stronger than an Energy kind, but it has an Higher Physical Weight than an Energy Shoot, lower quantity than Energy Shoots. Multi-Warhead Feature, thing that an Energy shoot can't really do...
2- Almost Inifinite (mostly Beam) / High Quantity Energy (another, fireballs mostly), like FS2 Primaries, however every shoot drains energy from the Engine, Custom Engines, have Custom PowerOut / Power Capacity and Power Re-Generation, no physical bullets, but Energy Bullets, can be as powerful as ammunition and even more, but require a really more advanced technology (as we see in real world), specially Laser Beam, Laser Cannon (launches a Ball a concentrated, which can make a massive explosion, depending on density), and Plasma shoot (the ball round one, I don't see this too used), Plasma Beam more powerful than Laser, but more Energy Comsuption than Laser, also most unestable, I am not sure if Plasma Beams is Affected by Gravity and pressure (it happens with Plasma TV, it's Plasma, but maybe different technology, so maybe not....). Without going to the exact term, Plasma is simply, Ionized Gas (principally conposed of Electrons, were the particles are partially charged) it occurs naturally on earth (good luck finding it), also the Sun and many Stars are composed of Plasma (get the Idea ?). If the Energy Output is not enough for the Energy consumption of all the Weapons, then the Ship can't shoot continously (this doesn't happen with Ammunition kind), considering the Gigas, it should need a whole day to re-charge all of it's SBF and URed, anyways, one shoot from every beams is enough to kill a full fleet.
So a Capital using Ammunition should also need to call a Support Ship, depending on the weapons, In Armored Core, the Engine produces both Power Output for Weapons and Afterburner, that means choosing and energy Weapon, would make you lost your Afterburner ability if you abuse too much, you can't do both things at the same time too long....
Seems that in some places Cannon, defines a Fireball (otherwise it says "xxxx Beam Cannon"), where Beam defines a.....well a Beam, that's it
I like also "Neutron Beam Cannon" (guess for what's it used...among other things), and my fauvorite, really strange and really powerful, "Anti-Matter Beam Cannon" (SuperNova Signature).....It seems to have the same power, not only the most advanced and complex, but also it's the kind of weapon with most Energy consumption, truly massive to be specific, only a ultra big ship would be able to carrie such a destructive weapon........
No one is probabily going to find those 2 energy types in US series, I'll suggest starting seeing some series or games from another countries, you know, the world is big..............(and so the universe seems to be....)
