Let's suppose we have a dyson swarm with an orbital trajectory analogous to the star-link constellation over earth, although only over a relatively small belt (lets say about 20 degrees from the equator) around the sun, producing in the ballpark of a few dozen exawatts. Obviously this would be a very thin swarm of satellites, as the sun is enormous and produces a truly incomprehensible amount of energy.
Each satellite is a massive kilometer-wide origami, a hexagon of polished foil bound to some supports. The mirror itself would be the primary reflector, focusing its light to a much smaller secondary reflector, a hexagon a few feet across, supported by extremely light struts that fold out as the mirror unfurls.
This focuses the light to a hole in the center of the primary reflector and out the back of the satellite. On the back is a tertiary reflector, which is a dynamically controlled phased-array lens, focusing the beam of light to a central collector satellite in a higher orbit, in a ring directly over the equator.
This outer ring is the collection ring, a few hundred kilometers over the mirrors, which orbit in a sort of squished torus. The collector satellites are, in comparison to the mirrors, very intricate, needing vast radiators to compensate for their pitiful efficiency and massive waste of heat.
The Method Of Operation
Now let's say we were a big bad terrorist organization that just wants the world to burn. Or let's suppose that the world has recently been freed from an evil imperialist autocracy, but they kinda want to make a comeback. (same evil autocracy that built those kind of dinky and underpowered long-haul ships)
If they wanted to cripple the solar system, or at least threaten to do so, what better way than to destroy or take control of the most critical piece of infrastructure? Easy! Just blow up the dyson swarm and in about a week, 19 billion people will be dying of starvation and civilization will be sent back to the early 20th century!
Currently, over earth, there is about ten thousand satellites orbiting earth at extremely varying speeds and angles, lots of which is space junk. A man by the name of Donald J Kessler proposed a serious future problem, called Kessler syndrome.
What if earths orbit becomes saturated enough that if a stray piece of debris hits a satellite, that satellite spews out enough debris to hit another, or two, or ten. Those satellites shoot out more debris, destroying more satellites. Eventually, earth orbit becomes a hellscape of flying debris, where no rocket can pass.
Humanity would be planet-bound, for the next thousand years or more, until the thin atmosphere in space causes all that junk to fall and burn up. What if we could make such a cascade happen in the dyson swarm?
The Kessler Swarm-destroying chaff bomb would be a bomb, possibly a nuclear one, possibly of some other, less destructive type, engineered to shoot out as much chaff as possible and trigger a Kessler Cascade, destroying the swarm mirrors, and clouding so much debris over its orbit that it is almost impossible to salvage.
I propose a nuclear weapon, possibly a pumped fusion warhead, surrounded in a blanket of liquid, possibly a non-ferrous metal. The weapon would explode, vaporizing some of it instantly and spewing tiny droplets at insane speeds. They solidify into tiny, impossibly plentiful bullets, moving at orbital speeds. (hundreds of thousands of kilometers per hour)
The debris would orbit around the sun, punching holes in the foil and destroying the phase-array control computers on each swarm mirror, or worse, causing a cascade of failures in that narrow belt of collector satellites over the top, punching holes in their big, delicate radiators and spewing off loads of debris.
How effective would this be? Would it even work?