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Mars_B4_Moon

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Registered: 2006-03-23

Posts: 9,776

Re: matter and anti-matter - Bringing back the old idea

Second OMG cosmic ray particle breaks physics again
https://cosmosmagazine.com/space/astrop … -particle/

“Amaterasu”: Astronomers detect highest energy cosmic ray since 1991

Astronomers involved with the Telescope Array experiment in Utah's West Desert have detected an ultra-high-energy cosmic ray (UHECR) with a whpping energy level of 244 EeV, according to a new paper published in the journal Science. It's the most energetic cosmic ray detected since 1991, when astronomers detected the so-called "Oh-My-God' particle, with energies of an even more impressive 320 EeV. Astronomers have dubbed this latest event the "Amaterasu" particle, after the Shinto sun goddess said to have created Japan. One might even call it the "Oh-My-Goddess" particle.

https://arstechnica.com/science/2023/11 … ince-1991/

'Amaterasu' particle: a new cosmic mystery
https://www.nanowerk.com/news2/space/newsid=64100.php

Last edited by Mars_B4_Moon (2023-11-23 20:35:15)

Calliban

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From: Northern England, UK

Registered: 2019-08-18

Posts: 3,796

Re: matter and anti-matter - Bringing back the old idea

This concept is relevant to the topic.
https://en.m.wikipedia.org/wiki/Antimat … propulsion

In an anti-matter catalysed IC fusion fission hybrid design, a comparatively small number of anti-protons could be injected into a uranium or plutonium outer shell, which is far beneath critical radius.  The antiprotons are drawn into the uranium nucleus, where they annihilate a proton, introducing enough energy to cause the nucleus to fission.  This produces a shower of neutrons, some of which result in more fission events.  If enough annihilation events occur simultaneously, the uranium shell will get hot enough to emit x-rays.  This will compress the inner lithium deuteride charge leading to fusion.  Fusion events generate more neutrons, causing more fission heating up the outer shell even more, driving more fusion, and so on.

A comparatively tiny amount of anti-matter can produce a high net energy gain by acting as a nuclear trigger.  This is just as well given the energy cost associated with producing anti-matter.  The most practical option is to generate anti-protons by bombarding the uranium shell with high energy protons.  This will generate pions, which then decay into anti-protons.

Last edited by Calliban (2023-11-24 06:09:24)

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"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

Void

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Registered: 2011-12-29

Posts: 7,831

Re: matter and anti-matter - Bringing back the old idea

That is interesting.  For purposes of terraforming a world, could Helium 3 and Deuterium be a next level of cascade, to make an explosion which would yield less Neutrons at that stage, and so be cleaner?

That would be for modifying regolith placement for resource extraction and to build canals, and perhaps to trigger land slides in where a danger exists for one to damage a settlement.

One thing I would be interested in would be to try to punch a hole in the permafrost in Hellas, to promote an Artesian well, if three is a Artesian water table there.  If that could be done, then the flow might be kept open by human manipulations.

That if it happened naturally would have lead to what we might call a Cryovolcanic eruption.  The result would be a pond/lake/sea, that would freeze over again as dust would cover the ice blocking sunlight, and evaporation would also damage the body of water.  But with such a creation humans and machines may prevent the refreezing and evaporation and envelopment in dust.

While some consider mining the Moon for Helium 3, I more hope that Helion will be successful in generating Helium 3 to use.

Such explosive devices might be rather good for Orion type drives as well.  I actually wonder if dust from Phobos and Deimos could be packed around such a device to become "Throw Mass".  As it might remain dust the solar wind may clean the space lanes of it.

This then would be possible in the asteroid belt, transferring to ice perhaps.

Bags of ice set around the explosive might allow another version of the Orion drive method.

https://en.wikipedia.org/wiki/Project_O … ropulsion)

So, a Neutron triggered start with an Aneutronic amplification packed with simple mass, might be more human friendly, and less dangerous to populated worlds.

Do you think I sort of have it close to correct?

Done

Last edited by Void (2023-11-24 08:20:09)

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Calliban

Member

From: Northern England, UK

Registered: 2019-08-18

Posts: 3,796

Re: matter and anti-matter - Bringing back the old idea

I suspect that aneutronic fusion would be more difficult in this hybrid context.  Fission is an integral part to how this works.  And the neutronic feedback from fusion reactions in the core results in a positive feedback effect, leading to more fission in the outer shell.  This in turn increases x-ray pressure on the fusion charge, driving more fusion, which releases more neutrons, and so on.

A while back, I looked into the idea of using a microgram nugget of fissile material at the heart of a lithium deuteride pellet.  This would function as a sort of spark plug, heating the core of a pellet as the fusion fuel compresses around it and sending a detonation wave through the pellet.  It is energetically much easier to produce high plasma density using driver assemblies than it is to heat even a small portion of the pellet.  And trying to drill through the pellet with a laser to create a central hot spot at the moment of peak compression, requires a level of accuracy in space and time that would be practically difficult to achieve.  So a microgram of fissile material at the pellet centre is exactly what is needed to trigger ignition conditions.  Such a small volume of fissile material adds little radioactivity.  But activating the trigger does require an intense shower of neutrons, to generate enough fission to heat the 'spark plug'.  So aneutronic fusion really won't do the job.

Assuming the spark plug idea is workable, the fast neutrons produced by the fusion pellet implosions are actually more valuable than the energy itself, because they can catalyse additional nuclear reactions.  A cheap source of fast neutrons allows the construction of hybrid fast reactors.  These can generate energy from thorium, depleted or natural uranium, without the need for enrichment, breeding or reprocessing.  On Mars, we could load metallic uranium or thorium fuel rods around the reaction chamber of a fusion reactor.  We switch the reactor on and bombard the fuel until about 20% of atoms have fissioned.  This increases the net energy yield of each fusion reaction by a dozen times.  A similar technology could provide nuclear thermal engines for large interplanetary ships.  In this case, the fuel would be cooled by hydrogen gas instead of liquid metal.  Hybrid fusion fission engines do not need to be launched with fissile material.  A purely fertile material like 232Th or 238U would do the job.  We do not need to wait for 239Pu to breed in the fuel, because the 14MeV fusion neutrons have enough energy to directly fast-fission 238U.

Last edited by Calliban (2023-11-24 16:18:40)

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"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

SpaceNut

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From: New Hampshire

Registered: 2004-07-22

Posts: 29,433

Re: matter and anti-matter - Bringing back the old idea

How antimatter engines could fly humans to other stars in just a few years

An antimatter engine could theoretically accelerate a spacecraft at 1g (9.8 meters per second squared) getting us to Proxima in just five years, Weed said in 2016. That's 8,000 times faster than it would take Voyager 1 — one of the fastest spacecraft in history — to travel about half the distance, according to NASA.
Even within our own solar system, an antimatter-powered spacecraft could reach Pluto in 3.5 weeks compared to the 9.5 years it took NASA's New Horizons probe to arrive, Weed said.

Calliban

Member

From: Northern England, UK

Registered: 2019-08-18

Posts: 3,796

Re: matter and anti-matter - Bringing back the old idea

One concept that recieved some attention about a decade ago, was antimatter catalysed fusion reactions.  The idea is that a negatively charged antiproton can replace an electron in the S-orbital of a hydrogen atom.  Because antiprotons are far more massive than electrons, the hydrogen nuclei are drawn close enough to allow them to fuse.  The concept is rather similar to muon catalysed fusion, but using antiprotons instead of muons.

Unfortunately, analysis suggested that each antiproton would only catalyse low single digits of fusion events before being drawn into the nucleus and annihalated.  Given the energy cost of producing antiprotons, this form of fusion is not expected to reach breakeven.

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"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."