What Is It For? (skip if desired)

It's been less than a decades since the Ilus system was cut off at its interstellar phase-gate, a few short years after the keidran were created and a disaster forced Sequoia R&DA to cut off the entire system to save humanity from their own mistake.

Our protagonist just got done getting marooned here and getting himself turned into a keidran. He's already fixed the tiny dyson swarm and gotten his cup of hot cocoa. Now he needs to fix the phase-gate and get home. Unfortunately the gate collapsed into a black hole with the mass of a small mountain and ate the phase-gate armature.

What Does It Do?

Basically, Ilus doesn't have the industrial might of the Terran system, and they can't import a replacement gate. So they have to jury-rig one with what they have. It runs on some yet-undiscovered quantum mechanics, and in short needs a large amount of power in a short window of time to be reopened.

Originally it had a system to do this easily, but it's gone and they can't make a replacement. With high-temperature superconductors and technology of such a caliber, even if its now second-hand scraps, how would you deliver thousands of peta-watts of electricity over the span of 3 to 5 seconds.

The machine would have dozens of jury-rigged hookups for 50 meter thick liquid-nitrogen-sheathed superconducting cables, and would operate at (relatively) low voltages, to minimize insulation issues.

The solution would just need to be single-use, frying itself it totally fine. Currently I planned on using some kind of superconducting rings that slowly build up a magnetic flux, to then use chemical explosive pumping to collapse the field in a blinding flash and with some luck, direct the energy flux into the machine through some seriously beefy cables.

Apart from an arbitrarily massive or unbelievably futuristic ultra-capacitors, or some handwavium-powered antimatter-to-electricity reactor, how would you approach such a problem?

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    $\begingroup$ First, not peta-watts but peta-joules, as you're speaking in terms of energy, not power. Still peta-watts are in place there as this will be the power that anything that says conductor would have to pass through without breaking, and so far there's nothing on Earth that can conduct that much. And second, there are things in superconductors like critical current (not voltage mind you!) that makes your proposed low voltage solution less likely to work compared to high-voltage one. $\endgroup$
    – Vesper
    Jan 16, 2023 at 6:12
  • $\begingroup$ @Vesper when I said relatively, I mean low enough that things like porcelain, oil and hard vacuum don't become routes for short-circuits. But duly noted. $\endgroup$ Jan 16, 2023 at 6:15
  • $\begingroup$ And the energy would be in the ballpark of the mass of a primordial black hole, following E=Mc2 $\endgroup$ Jan 16, 2023 at 6:21
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    $\begingroup$ I think the best way to generate this kind of power is to deliver that to the spot in form of a nuke, anyway your gate rig should be big enough to initially allow 10^18W income from somewhere to not overheat any component, so a nuke combined with some energy converters that would capture a good load of released energy and allow for a 1.21 jiggawatt peak conversion rate could just do. Still in the handwavium range, if oyu ask me. $\endgroup$
    – Vesper
    Jan 16, 2023 at 6:35
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    $\begingroup$ Hard vacuum is conductive - see multipaction and akso field emission. $\endgroup$
    – Jasen
    Jan 16, 2023 at 9:57

2 Answers 2


Your question is slightly ambiguous... are you delivering a few exajoules of energy over a few seconds, or a few exawatts of power over a few seconds? There's potentially an order of magnitude difference in power and energy levels there (10EW for 10s is 100EJ, 10EJ over 10s is 1EW).

10 exajoules is the equivalent to ~2.4 gigatonnes of TNT, or the complete annihilation of ~111kg of antimatter. That's quite a bang, but the sort of civilization you have in mind should be able to rustle up enough nuclear explosives of some form or the other (Tellar-Ulam is fine, you don't need to brew up a load of antimatter if you don't already have some to hand) to generate that much bang and plenty more.

There's a thing that works a little like a plasma rocket in reverse, the magnetohydrodynamic generator. Throw hot, fast-moving plasma in one end, get cooler, slower moving plasma out of the other end, plus volts. You don't need a sustained power-generating infrastructure, so instead what you can build are nuclear pulsed-power units... these would look a bit like a Casaba-Howitzer device used for either pushing Orion drive spacecraft or as weapons, strapped to an MHD generator on a long superconducting tether. Pull the pin, nuke goes foom, generates a directional-ish blast of plasma down the throat of the MHD generator which then briefly generates a nice strong current before it gets blown to bits.

Repeat as much as necessary. The nice thing about these is that the individual pulse generators can be built and tested independently, so you can practise getting them right and sorting out timing issues. Build a whole load of them, fuelled with whatever nuclear explosive you like best, let em rip.

Currently I planned on using some kind of superconducting rings that slowly build up a magnetic flux, to then use chemical explosive pumping to collapse the field in a blinding flash and with some luck, direct the energy flux into the machine through some seriously beefy cables.

Superconducting magnetic energy storage is a lot more sensible, but clearly a lot less awesome than a timed firework display of directional nuclear explosions. Superconducting homopolar generators might also work... they were delivering substantial amounts of oomph back in the 60s, and technology has marched on a bit since then. Less boom, but you get to spin them up over time which has its own kind of drama that a silent idle nuke or superconducting coil just can't provide.

I haven't found out much about making a explosively pumped flux compression generator from high-tech superconductors, but given the capabilities of the regular kind of EPFCGs (you could probably manage gigajoules at giga-amp currents with present day tech) you might even be able to get away with simply scaling up simple tech to get what you need.

  • $\begingroup$ Ah! MHDs! I didn't think of that! Well... seeing as SMESs and EPFCGs (ACK! Even the acronyms are a mouth full!) need a starting current to amplify, you could get away with combining them and having both the slow, anxiety-filled charge-up and then nuclear fireworks! Fantastic. $\endgroup$ Jan 16, 2023 at 16:38

Use your hole.

You have a handy little black hole at your disposal. I will assume it is an extremal black hole because it is small and it is still there.


Black holes become electrically charged when charged stuff falls into them. Physicists calculate that black holes have an “extremal limit,” a saturation point where they store as much electric charge as possible for their size. When a charged black hole evaporates and shrinks in the manner described by Hawking, it will eventually reach this extremal limit. It’s then as small as it can get, given how charged it is. It can’t evaporate further.

If you feed mass to this black hole, it will trivially increase its mass and size but deliver all the charge that was in the mass. The black hole must get rid of the charge. A good way would be to send it away as electrons. If you have your black hole wired up before you feed it, you will capture the surge of charge produced by your hole food.


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