Goodbye conservation of energy. Hello near-c rocks. Splat!
Hello near-c rocks. Splat!
I'm over your cities, killing your men.
I'm in your Past Light Cone, killing your grandparents.
The concept of all of those densely packed ions is simply repulsive.
Even more repulsive.
Zap, you're dead as soon as you show up.
If fusion was easy, the sun would explode.
Useless against real warships and inferior to one shot or multiuse missiles.
Without the above they're too fragile to survive if they carry a reasonable fuel fraction. Plus, if there was anybody for them to fight, then why aren't they here already?