Once upon a time there was an interstellar kingdom with access to hundreds of planets through wormholes. Geniuses or luck gave them magnetic monopoles. They exist!!! The next bit is somewhat magical so I will handwave it. Purportedly every 110 years on each of the hundreds of planets at X locations a dozen magnetic monopoles are captured. Something tells me X has to be huge. So I want to determine X given a harvest period of nine centuries.
From https://www.orionsarm.com/eg-article/48572566653b6 a bit more fiction on the subject:
Powerful military forces can use this technology to create compact and powerful monopole-catalysis "total conversion" bombs, which is essentially a fusion-total conversion explosive device with more controllability, lethality, and shelf-life than similar antimatter weapons. (Increased lethality comes from much lower production of muons than antimatter devices; which concentrates the energy density of the monopole bomb compared to the "fizzle" of an antimatter device. Controllability comes from doping the fusing plasma with other exotic particles to generate reactions with other side effects, such as axion or Higgs production.)
Related to the above somewhere in https://physics.stackexchange.com/questions/446938/runaway-monopole-catalyzed-baryon-decay#446971 an answer says that a monopole needs to travel through 11 meters of copper to induce proton decay for antimatter and annihilation.
The goal is to disable a starship. As a proxy I am using an aircraft carrier. Since the specs of those are not open to the public, any vessel of similar dimensions will do. According to Wikipedia the existence of magnetic monopoles would mean updating the Maxwell equations. A book of Michio Kaku and other sources say that magnetic monopoles are useful to generate energy. The kingdom is less interested in this. How many magnetic monopoles are needed to disable a decent ship/aircraft carrier? Disable defined as unable to move and otherwise damaged.
Extra comments for Vesper: starships move through plasma engine, propulsion. A monopole would be half of a magnet. https://simple.wikipedia.org/wiki/Magnetic_monopole As I said Maxwell equations would apply with modifications. If you want to get close to ships they are bound to shoot, so some distance is required. Assume range of modern navy ships for sake of argument.
Extra comments: I base the handwave part on https://www.nature.com/articles/305673a0 about capture. I am saying for the sake of argument that the Stanford event gave a dozen magnetic monopoles. And https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.48.1378
About mass: since particle physicists have been looking for magnetic monopoles at higher and higher energies monopoles must be heavier than protons by a large factor. But not enough for a black hole, I hope. Also apparently if you have them, you can create more monopoles by smashing them together which is a high energy event. This is all conjecture of course. According to https://physics.aps.org/articles/v10/s137 magnetic monopoles can be made through heavy ion collisions and in neutron stars. From https://physicstoday.scitation.org/do/10.1063/PT.6.1.20220222a/full/
They’re the hypothetical analogues to electric charges in Maxwell’s equations. In fact, their existence would make the equations more symmetrical:
Most experiments have focused on elementary-particle collisions that could produce monopoles that are point-like particles.
In November 2018 a lead–lead collision experiment at the LHC succeeded in producing a magnetic field with a strength of 1016 T, the strongest ever observed in the universe. MoEDAL has now published its results, and although no magnetic monopoles were observed, the team did exclude the possibility of monopoles with masses smaller than 75 GeV, which is roughly 80 times as large as the mass of the proton.
But point-like and composite monopoles are expected to strongly couple to photons.