After robotic mining silos have crumbled Mercury into chunks of metal and rock, after Uranus and Neptune have nudged into mutual orbit to siphon gas and ices toward their center of mass, after every mote of carbon-bearing asteroid has become graphene: we will set our sights on the sun. How should we harvest its immense energy? How to capture its mass, for our own fusible power, and for the resultant elements? How do we eat a star?
Isaac Arthur compiled a few options. I have a better one: reflect sunlight back onto the photosphere, to ‘fluff’ the gaseous envelope, and run enormous electric coils, generating magnetic fields which siphon ionized plasma onto ‘gas traps’. This is the cheapest, fastest way to lift gas out of the gravity well of a star. Consider:
The sun spews light and ionized particles in every direction. These outward gusts are sufficiently strong to keep thin panels ‘aloft’, like a bird hovering on a thermal updraft. Mirrored panels provide the most ‘lofting’ force, and they conserve solar energy; the light shines back down onto the sun, heating it, and re-emitting it outward again, later.
If the sun is surrounded by such floating mirrors, the amount of sunlight reflected is immense. This reflected light serves to heat smaller targets on the sun’s outer layer of gas. When temperature rises, gases expand — and the expansion of the gas surrounding the sun is equivalent to lifting that gas away from the sun’s gravitational well. This is like having sunlight-powered rockets haul gas away from the sun, except you need no rockets!
The sun does not need to be surrounded, for us to begin siphoning gas — even a single degree of arc would be plenty! When the surface of the sun heats and expands, this heating extends the reach of coronal mass ejections. The bulge of gas supports larger ‘waves’. So, periodically, enormous swirls of ionized gas belch forth, to distances much greater than they would have, had the corona not been heated by mirrors. The ionized gas is easier to ‘grab’ when it is so far from the core of the sun. But, how to wrap your fingers around it? Magnets.
An electric current in a coil generates a magnetic field. And, that magnetic field acts upon charged particles. If the massive, floating mirrors also operated equally massive coils of electrical wire, then the ionized discharges from the sun’s heated corona would be funneled by the magnetic field, impacting the mirror’s center. That is where hydrogen ions are enveloped by a ‘waterskin’ of graphene, to be cooled condensed for storage. I have a feeling that an electromagnet swooping over a CME can be more compact and attainable than a magnetic ring hovering over the sun’s polar region, a requirement of the ‘Huff n Puff’ method.
The sun has much more matter and energy than all the planets combined. Yet, we cannot easily access the sun’s potential. With an efficient lofting and capture mechanism, the gas retrieved from the sun yields energy from fusion that is well over 1,000 times greater than the energy needed to lift that gas out of the sun’s gravity well. It pays for itself, so long as you have an efficient technique. Mirrors, by heating and lofting surface gasses as ionized ejections, and electromagnets, by siphoning and concentrating those ionized gasses for sequestration, are our best bet for harvesting our star.
We could continue this heat-and-funnel process until the sun’s mass dipped below the level necessary to sustain fusion. At that point, we will need to lob a huge ball of iron and nickel along an elliptical path, to tug wisps of gas into higher orbit. Eventually, we could strip the gasses away completely, until only a lump of metals remained. That lump would be a gold mine greater than Mercury, able to sustain the needs of industry for millennia.
Cracking the Core Open
The biggest part of the puzzle, when eating a star, is how to crunch down on that tasty, metallic core. You’ll need a steep elliptic flyby from a sturdy space vessel, which delivers an enormous nuclear warhead that propels a tiny ‘fleck’ of the core upward, and subsequently catches that core fragment before it falls back into the gravity well of the sun’s core. From various directions, these orbiting structures would flake-away the metal core of the sun, until such a small portion remained that its gravity could be tolerated by robots and rockets. We’ll get there soon enough.