Fusion-anti matter hybrid spaceship propulsion?

[totoro]

But... there isn't that much text written on such propulsion, available online. The Wiki article is not very helpful. So can anyone help me understand it?
What I gathered is that the gist of it is this: you have a fusion reaction which is somehow spiced up with antimatter. But that leaves me with questions:
Does it involve basically a normal fusion reactor (lets say that within 100 or 200 years such tech would be wide spread) ?
Does it then involve, besides the fuel for the fusion, holding a certain amount of anti-matter within the ship? Enough for repeatedly adding AM to the reaction, during the entire trip?
How hard is it to contain antimatter, and store it for years if necessary? I understand that creating antimatter is insanely power demanding and thus expensive, but that it can be done. But how far along is the containment technology? Are there indications that year long containment could be achievable within 100 or 200 years?

Finally, just how would the power, emitted by the reactor be harnessed and directed so the whole ship can accelerate or decelerate at 1 G, eventually achieving 0.5 speed of light?

 

[shin_getter]

Sounds like this thing:
https://en.wikipedia.org/wiki/Antimatter-catalyzed_nuclear_pulse_propulsion

So, basically, Orion (nuclear blast propulsion) with antimatter triggering fusion bombs.

As for containing antimatter, magnetic/laser traps work, though no one has built it at the necessary scale and time frame, but it should be workable in principle. No one have the energy generation to produce anti-matter at the scale required either.

It is one of those engineering projects that makes sense for a K2 civ so most talks about it is very premature.

 

[totoro]

While using fusion bombs is one option, a more interesting option to me is this:

Unconventional Rocket Drives - Antimatter Propulsion

Under the beam-core antimatter propulsion paragraph.

Sadly, I still don't quite understand how that'd work. Does the article suggest the fusion reactor would be fixed inside a spaceship? And then the antimatter would be periodically added to the reaction? And then that there would somehow (how?) power be radiating out of the reactor? And then that some magnets would be re-directing that power (but in what form is that power?) so it's ejected out of the spaceship, thus accelerating the ship itself?

 

[TomS]

While using fusion bombs is one option, a more interesting option to me is this:

Unconventional Rocket Drives - Antimatter Propulsion

Under the beam-core antimatter propulsion paragraph.

Sadly, I still don't quite understand how that'd work. Does the article suggest the fusion reactor would be fixed inside a spaceship? And then the antimatter would be periodically added to the reaction? And then that there would somehow (how?) power be radiating out of the reactor? And then that some magnets would be re-directing that power (but in what form is that power?) so it's ejected out of the spaceship, thus accelerating the ship itself?

Just reading that for the first time, but my impression is that the Beam-Core antimatter drive does not use fusion at all; it uses matter-antimater annihilation. So equal amounts of protons and antiprotons are injected into a magnetic nozzle, they annihilate each other generating charged and neutral pions (pi mesons). The charged pions (and their positron/electron decay products) can be directed using magnetic fields to generate thrust; the neutral mesons decay into gamma rays, which the authors hope can be reflected and also used to create some extra thrust.

This seems more like an exercise in theoretical physics than something that is ever likely to work IRL.

 

[totoro]

Hm, true. That paragraph may not include fusion at all. I guess the third and the fourth paragraphs are more interesting then.

Antimatter Catalysed Micro Fission/Fusion Drive​

Which seems to lack the mention of pulse, so it may not be about ejecting nuke bombs but somehow containing the reaction and redirecting power?

And

Antimatter Initiated Microfusion Drive​

Which seems to be roughly similar but requires more antimatter. Though here it definitely mentions there is fusion product particle matter expelled through a magnetic nozzle.

 

[bobbymike]

Antimatter Could Unlock a Radical New Future of Interstellar Travel

Interstellar travel is only something humanity has achieved in science fiction — like Star Trek's USS Enterprise, which used antimatter engines to travel across star systems.

www.sciencealert.com

 

[bobbymike]

Beam me to the stars: Scientists propose wild new interstellar travel tech

"Chemical rockets that we use today, even with the extra speed boost from flying by planets, or from swinging by the sun for a boost, just don't have the ability to scale to useful interstellar speeds."

www.space.com

 

[Scott Kenny]

But... there isn't that much text written on such propulsion, available online. The Wiki article is not very helpful. So can anyone help me understand it?

Hopefully this link will help. It is rather math-dense, however, because it's intended as a guide for people trying to write accurate science in their fiction.

Engine List 3 - Atomic Rockets

www.projectrho.com

What I gathered is that the gist of it is this: you have a fusion reaction which is somehow spiced up with antimatter. But that leaves me with questions:
Does it involve basically a normal fusion reactor (lets say that within 100 or 200 years such tech would be wide spread) ?

One proposed design uses antimatter as an "afterburner" in a standard fusion-thermal rocket.

Liquid H2 gets pumped through or around a reactor to cool it and the heat causes it to expand a lot. Then you dump antideuterium into the already hot exhaust and that adds even more energy. It normally takes very little antimatter to add a whole lot of energy to anything; fusing hydrogen or D+3He only converts hundredths or thousandths of a gram of matter to energy (per ~5 grams of D+3He), while antimatter converts far more mass into energy.


There's another version that is pure antimatter.
This uses the fact that whole atoms of matter and antimatter produce charged particles that you can then use a magnetic nozzle to direct away from your ship. (the other option for antimatter is only electrons and positrons reacting, but that just makes pure uncharged gamma radiation and is therefore useless for propulsion. Great for weapons, however!)

Engine List 3 - Atomic Rockets

www.projectrho.com

Does it then involve, besides the fuel for the fusion, holding a certain amount of anti-matter within the ship? Enough for repeatedly adding AM to the reaction, during the entire trip?

In the version that is an afterburner design, yes. You would have to carry an immense amount of antimatter around with you. This is not going to endear you to anyone else, they will likely insist that you do not bring that flying cataclysm anywhere near their habitable planets, thank-you-very-much.

The version that runs on a pure antimatter reaction is most closely related to the Orion/Daedalus continuously-detonating drives.

How hard is it to contain antimatter, and store it for years if necessary? I understand that creating antimatter is insanely power demanding and thus expensive, but that it can be done. But how far along is the containment technology? Are there indications that year long containment could be achievable within 100 or 200 years?

Well, storing antimatter as antideuterium slush in an electromagnetic containment field is the usual theoretical model.

You then need to have a way to rapidly kick that cryocell away from the ship in the event of the electromagnetic containment field failing. I'd suggest starting with electromagnetic clamps that are wired into the circuit with the containment field, such that the containment field flickering would result in releasing the clamps. You then have springs and some storable-hypergolic rockets to push that cryocell away as fast as possible.

Finally, just how would the power, emitted by the reactor be harnessed and directed so the whole ship can accelerate or decelerate at 1 G, eventually achieving 0.5 speed of light?

Depends on engine design. My preferred version uses an electromagnetic nozzle, so that you need to carry less shielding between you and the antimatter reaction chamber.

However, as you're screaming along at those speeds, interstellar hydrogen is going to impact the bow of the ship. You're going to need to do something fancy to deal with the radiation this causes.