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An old NASA news article I came across states that a solar flare observed in 2002 produced around a half-kilo of antimatter:

https://www.nasa.gov/vision/universe/solarsystem/rhessi_antimatter.html

How realistic would it be to harvest the antimatter from a solar flare? Presumably, a mission to obtain the antimatter (with the intention of using it to power an interstellar spacecraft) would need to overcome some of the following obstacles:

  1. Survival: the spacecraft and harvesting apparatus would need to be able to withstand violent, high-temperature conditions.

  2. Prediction: the spacecraft would need to be located in a region where a solar flare is likely to happen, before it happens (presumably near a sunspot), and then to stand idly by for a period of months (or even years) waiting for a flare.

  3. Collection: the harvesting apparatus would need to somehow isolate the stream of antiparticles released in the solar flare (perhaps using very strong magnets), collect them into storage and then deliver them to a spacecraft.

Assuming cost is not an issue, how realistic would it be for this mission to take place within, say, the next 50 years? Which of the obstacles I outlined is the most difficult for modern human civilization to overcome? Are there other problems I haven't thought of that would make this idea impossible?

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    $\begingroup$ Solar flares are biggg objects. That half kilogram of antimatter is spread out over a very large volume. $\endgroup$ – AlexP Oct 20 '20 at 18:58
  • $\begingroup$ True, although one would also only need to harvest a small fraction of it (perhaps around a gram). Maybe one could have a small fleet of harvesting spacecraft spread out over the region of the solar flare? $\endgroup$ – Framazu Oct 20 '20 at 19:06
  • $\begingroup$ you will get about 3.125e-13 kg of antimatter per kg of matter you harvest, that ain't alot (for a cme, not just a solar flare, but ridiculously low number is still relevant) $\endgroup$ – Topcode Oct 20 '20 at 19:08
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It will probably be cheaper and faster to make it in a lab.

Cost to produce 1g of Antimatter in a lab:

  • 1999 62.5 trillion USD
  • 2006 25 billion USD
  • In 7 years, The cost per gram has gone down by 1:2500.
  • I can find no more recent cost estimates, as we haven't attempted mass production, we're more interested in using CERN to figure out physics than mass produce antimatter. Lets assume that no technological advances have occurred between 2006 and 2020 for sake of simplicity.

Resuming antimatter production research in 2020, and extrapolating that rate of improvement;

  • 2020: 25 billion USD
  • 2027: 10 million USD per gram.
  • 2034: 4 thousand USD per gram. $2million / kg.

I'm stopping the extrapolating here (otherwise by 2050 antimatter is cheaper than bananas, and that seems silly), however assuming technology makes 2 similar leaps between now and 2050 that it did between 1999 and 2006, and we're looking at $1 million to make in a lab what you'd capture from a solar flare.

Just to play it safe, lets allow an extra 16 years for those innovations to occur (2050 is a nice round number). We've got economies of scale working in our favour, as well as being able to replace phd physicists with minimum wage technicians.

This crazy cost extrapolation is not without precedent: Transistor costs dropped 12 orders of magnitude in 40 years, and 21 orders of magnitude in 90 years if you include vacuum tubes

The parker solar probe cost 1.5 billion USD. Assuming your anti-matter collector is as expensive as that (which is very generous), the startup costs of the collector would be better spent creating 750kg of antimatter in a lab.

Even if we only get 1 leap in tech in the next 30 years, the cost of the spacecraft to capture flares would pay for 150 grams of antimatter. Enough for whatever engine you can imagine.

With solar flare frequency varying from several per day to 2-per-month over its 11 year cycle, 750kg of antimatter would take several years to collect naturally even if you could capture every single flare and every single gram - which is pretty unrealistic to expect from orbital mechanics. You may be able to capture 1 in 10 using orbital manoeuvring, you're looking several decades to make similar quantities.

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    $\begingroup$ I'm left with the thought that harvesting the energy of the solar flare itself to manufacture antimatter might be more effective than sifting the flare for AM. $\endgroup$ – Ruadhan Oct 21 '20 at 10:40
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    $\begingroup$ Though the cost per gram may decrease as you say from now to 2050, I'm not sure we'd actually be physically capable of producing quantities on the order of grams. The total production in the history of particle accelerators like CERN and Fermilab is on the order of nanograms. Really depends on what those technological leaps are I guess... $\endgroup$ – Framazu Oct 21 '20 at 19:47
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Good Question - because it solved another problem, how to control solar flares.

Plasma is composed atomic nuclei, (atoms stripped of some or all their electrons), so it has a positive charge.

A plasma stream generates and reacts to magnetic fields. A collection of plasma streams could be generated from a space craft in a solar orbit using solar power to power the magnetic fields controlling the Plasma.

These plasma control streams, PC-Streams for short, can control the solar flare plasma, from a safe distance.

Directed toward the flare PC-Streams could be used to direct some or most of the positive particles from the flare for sorting at a anti-matter collection and processing plant, A-Matter generator for short, in another orbital volume and also away from space habitats ,settlements (including Earth) or space lanes.

Orbital Solar Power Station A side point. At an orbit half way from Earth to the Sun pushes about 5 kilo Joules (Kj) of energy per square meter per second. In 52 days over an area of 4 square kilometers the total energy is over 9 times 10 power 13 Kj

A half kilogram of anti-matter combined with an equal amount of normal matter generates slightly less than 9 times 10 power 13 Kj

Bottom Line - costs.

As the mechanism can be used to protect humans and property, it is in the words of Douglas Adams Somebody else's problem and the insurance people will get it done.

The A-Matter Generator, could also produce A-Matter Directly using the energy from the Sun.

Nice Job.

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