Method for storing antimatter

[scienceguy]

Antimatter would be an ideal fuel for long duration space travel because of its high energy density, however storing antimatter is difficult.

What follows is a proposed method for storing antimatter long term with minimal energy requirements. What you need is a square box perhaps made of plastic with sheets of aluminum foil acting as parallel plate capacitors along every side of the box. The electric fields from the sheets of aluminum contain the antimatter. To release the antimatter a bit at a time, simply move a hole in the sheets and plastic wall until they align. Please see diagrams.

The corners of the box won’t leak antimatter because the electric field vectors at the corners add up to make a vector pushing in the opposite direction. Just make sure the aluminum sheets extend farther than the edge of the box.

calculations

Say there are 10^6 positrons inside the plastic box. If the box is 1 m x 1 m x 1 m then there will be on average 1 cm between positrons. The electric field needed to keep the positrons contained is then

E = kq/r^2

E = (10^10 N m^2/C^2)(10^6)(1.6 x 10^-19 C)/(0.01 m)^2 = 16 N/C

The energy needed to charge a capacitor to 16 N/C is

u = (1/2)e0 E^2 = (1/2)(8.85 x 10^-12 F/m)(16 N/C)^2 = 1.1 x 10^-9 J

Thus the energy needed to store antimatter by this method is minimal. The energy is much more if you want 10^9 positrons in the box. I will show that calculation too.

Say there are 10^9 positrons inside the plastic box. If the box is 1 m x 1 m x 1 m then there will be on average 1 mm between positrons. The electric field needed to keep the positrons contained is then

E = kq/r^2

E = (10^10 N m^2/C^2)(10^9)(1.6 x 10^-19 C)/(0.001 m)^2 = 1.6 x 10^6 N/C

The energy needed to charge a capacitor to 1.6 x 10^6 N/C is

u = (1/2)e0 E^2 = (1/2)(8.85 x 10^-12 F/m)(1.6 x 10^6 N/C)^2 = 11 J

[Nilof]

My initial feeling is that this will not work because of Earnshaw's theorem. For electromagnetic storage to work you either a setup that requires the full theory of electrodynamics, not just electrostatics. Alternatively, you can have some parameter of the setup to change in response to perturbations from the desired equilibrium, through active control or nice material properties. But electrostatics alone won't work.

[aceshigh]

isn´t it a bit of wishful thinking that nobody at CERN and everywhere else would have thought of such simple design, it it were that easy?

[Hanelyp]

In the apparatus as illustrated, the electric field inside the box is zero, neglecting the charged particles inside.

[scienceguy]

In the apparatus as illustrated, the electric field inside the box is zero, neglecting the charged particles inside.

Oops! Well back to the drawing board!

[JulesVerneATV]

Scientists Found One of the Heaviest Antiparticles Ever
https://www.popularmechanics.com/science/a64554409/antihyperhelium-lhc-alice/

perhaps somewhat sensationalist and the realm of scifi?

Antimatter rocket 300x stronger than fusion could reach nearby stars much faster: Study
https://interestingengineering.com/space/antimatter-rocket-engine-300x-stronger
The new study identifies two specific annihilation reactions particularly well-suited for space missions.

Producing and storing antimatter is difficult and expensive. Current methods yield amounts far below the quantities needed to propel spacecraft.

As of now, one of the most promising candidates for antimatter fuel is antihydrogen.

“Antihydrogen is the simplest pure antimatter atom. Its stability, long-term storage capability, and simplicity of production give it the potential to scale up its production and storage capacities,” explained the researchers.

However, the production of antihydrogen is still in the early stages of development.

Space may be filled with more antimatter than we can explain
https://www.newscientist.com/article/2450590-space-may-be-filled-with-more-antimatter-than-we-can-explain/

The AMS-02 on the ISS has, as of 2021, recorded eight events that seem to indicate the detection of antihelium-3
https://www.newscientist.com/article/2275563-antimatter-stars-may-lurk-in-the-solar-systems-neighbourhood/

Giant Space Magnets
https://www.science.org/content/article/giant-space-magnet-may-have-trapped-antihelium-raising-idea-lingering-pools-antimatter

2024 article

object, linked to the pulsar PSR B2224+65, was captured in dramatic detail with X-ray and optical imagery.
https://www.spacedaily.com/reports/NASAs_Chandra_and_Hubble_showcase_fiery_cosmic_Guitar_Nebula_in_motion_999.html

The filament provides insights into how particles, including electrons and positrons, escape the confines of the nebula. When the pulsar passes through denser gas regions, some particles break free, flowing along magnetic field lines in interstellar space.

Movies constructed from Chandra and Hubble observations capture the movement of the pulsar and surrounding structures over decades. The Chandra movie incorporates data from 2000, 2006, 2012, and 2021, while the Hubble version includes data from 1994, 2001, 2006, and 2021. These movies show the pulsar and its filament traveling towards the upper left, although the guitar-shaped outline of the hydrogen nebula remains static.

A recent study has tied variations in hydrogen density to changes in the number of particles escaping from the pulsar. These shifts cause the X-ray filament to subtly brighten and fade, mimicking the effect of a "cosmic blowtorch."

This antimatter version of an atomic nucleus is the heaviest yet
https://www.newscientist.com/article/2444715-this-antimatter-version-of-an-atomic-nucleus-is-the-heaviest-yet/
Smashing gold nuclei together at high speeds billions of times has resulted in 16 particles of antihyperhydrogen-4, a very exotic and heavy form of antimatter

Antimatter: Scientists freeze positronium atoms with lasers
https://www.bbc.com/news/science-environment-68349448

“Antihyperhelium-4" The Heaviest Known Antimatter Hypernucleus
https://medium.com/@erwinlancaster/antihyperhelium-4-the-heaviest-known-antimatter-hypernucleus-00692eec67d2

[spacenut]

We have to find some di-lithium crystals.  Ok, storage of antimatter may be a few years away.  We still haven't controlled nuclear fusion to produce power.  Based on what the links are saying, maybe storing antimatter is easier than controlling fusion. 

[scienceguy]

What about using a toroid of permanent ring magnets and storing the antimatter inside? Please see attached diagram.

[24Launch]

I remember reading that Fermilab has been producing and storing antimatter and my understanding was it was fairly long term.  I know the OP is focusing on portable containment instead of an impracical campus-wide lab, but perhaps the containment method is still relevant.  Interesting articles though they're from 2014:

The Importance of Antimatter Research (talks about storage)
https://www.fnal.gov/pub/science/inquiring/questions/antimatter3.html

Fermilab's Antimatter Production Rate
https://www.fnal.gov/pub/science/inquiring/questions/antimatterprod.html

[StraumliBlight]

Breakthrough in antimatter production [Nov 18]

In a paper published today in Nature Communications, researchers at the ALPHA experiment at CERN’s Antimatter Factory report a new technique that allows them to produce over 15,000 antihydrogen atoms – the simplest form of atomic antimatter – in a matter of hours.

“These numbers would have been considered science fiction 10 years ago,” said Jeffrey Hangst, spokesperson for the ALPHA experiment. “With larger numbers of antihydrogen atoms now more readily available, we can investigate atomic antimatter in greater detail and at a faster pace than before.”

To create atomic antihydrogen (a positron orbiting an antiproton), the ALPHA collaboration must produce and trap clouds of antiprotons and positrons separately, then cool them down and merge them so that antihydrogen atoms can form. This process has been refined and steadily improved over many years. But now, using a pioneering technique to cool the positrons, the ALPHA team has increased the rate of production of antihydrogen atoms eightfold.

This spectacular advance in the production rate is all down to how the positrons are prepared. First, the positrons are collected from a radioactive form of sodium and contained in what is known as a Penning trap, where fine-tuned electromagnetic fields hold the antiparticles in place. However, they do not remain still. Like a tiger in a zoo, the positrons circle their cage, causing them to lose energy. This cools the cloud of positrons, but not enough for them to efficiently merge with the antiprotons to form antihydrogen atoms. So, the ALPHA team recently tried a new approach, which was to add a cloud of laser-cooled beryllium ions to the trap so that the positrons would lose energy in a process called sympathetic cooling.

This got the positron cloud down to a temperature of around -266 °C, making it much more likely to form antihydrogen atoms when mixed with the antiprotons. This approach allowed over 15,000 antihydrogen atoms to be accumulated in under seven hours. To put this into perspective, it took a previous experiment 10 weeks to accumulate the 16,000 antihydrogen atoms required to measure the spectral structure of antihydrogen with unprecedented precision. “The new technique is a real game-changer when it comes to investigating systematic uncertainties in our measurements.  We can now accumulate antihydrogen overnight and measure a spectral line the following day”, said Niels Madsen, deputy spokesperson for ALPHA and leader of the positron-cooling project.

[daedalus1]

Production, yes.
But what is the lifetime of the atoms?

[Robotbeat]

Breakthrough in antimatter production [Nov 18]

In a paper published today in Nature Communications, researchers at the ALPHA experiment at CERN’s Antimatter Factory report a new technique that allows them to produce over 15,000 antihydrogen atoms – the simplest form of atomic antimatter – in a matter of hours.

“These numbers would have been considered science fiction 10 years ago,” said Jeffrey Hangst, spokesperson for the ALPHA experiment. “With larger numbers of antihydrogen atoms now more readily available, we can investigate atomic antimatter in greater detail and at a faster pace than before.”

To create atomic antihydrogen (a positron orbiting an antiproton), the ALPHA collaboration must produce and trap clouds of antiprotons and positrons separately, then cool them down and merge them so that antihydrogen atoms can form. This process has been refined and steadily improved over many years. But now, using a pioneering technique to cool the positrons, the ALPHA team has increased the rate of production of antihydrogen atoms eightfold.

This spectacular advance in the production rate is all down to how the positrons are prepared. First, the positrons are collected from a radioactive form of sodium and contained in what is known as a Penning trap, where fine-tuned electromagnetic fields hold the antiparticles in place. However, they do not remain still. Like a tiger in a zoo, the positrons circle their cage, causing them to lose energy. This cools the cloud of positrons, but not enough for them to efficiently merge with the antiprotons to form antihydrogen atoms. So, the ALPHA team recently tried a new approach, which was to add a cloud of laser-cooled beryllium ions to the trap so that the positrons would lose energy in a process called sympathetic cooling.

This got the positron cloud down to a temperature of around -266 °C, making it much more likely to form antihydrogen atoms when mixed with the antiprotons. This approach allowed over 15,000 antihydrogen atoms to be accumulated in under seven hours. To put this into perspective, it took a previous experiment 10 weeks to accumulate the 16,000 antihydrogen atoms required to measure the spectral structure of antihydrogen with unprecedented precision. “The new technique is a real game-changer when it comes to investigating systematic uncertainties in our measurements.  We can now accumulate antihydrogen overnight and measure a spectral line the following day”, said Niels Madsen, deputy spokesperson for ALPHA and leader of the positron-cooling project.

This is a few microjoules, fwiw. You should be able to see the flash of these as they annihilate and the gammas make a hot plasma.

[laszlo]

Production, yes.
But what is the lifetime of the atoms?

Infinite (or close enough for human purposes), as long as they don't touch any matter (or get used in an anti-fusion reaction or some other exotic thing).

Mind you, 15,000 atoms is 0.4 x 10^-19 grams, not a really useful amount for fuel purposes. This is still a research lab achievment for now.

[daedalus1]

Production, yes.
But what is the lifetime of the atoms?

Infinite (or close enough for human purposes), as long as they don't touch any matter (or get used in an anti-fusion reaction or some other exotic thing).

Mind you, 15,000 atoms is 0.4 x 10^-19 grams, not a really useful amount for fuel purposes. This is still a research lab achievment for now.

Yes, I meant in reality. How long will the atoms last until contact with normal matter.

[laszlo]

Production, yes.
But what is the lifetime of the atoms?

Infinite (or close enough for human purposes), as long as they don't touch any matter (or get used in an anti-fusion reaction or some other exotic thing).

Mind you, 15,000 atoms is 0.4 x 10^-19 grams, not a really useful amount for fuel purposes. This is still a research lab achievment for now.

Yes, I meant in reality. How long will the atoms last until contact with normal matter.

The only record I've found for anti-hydrogen was set in 2011 and is 17 minutes. But if they're talking about creating 15,000 atoms in a few hours to experiment with then they'd need storage that lasts at least that long.

[StraumliBlight]

The only record I've found for anti-hydrogen was set in 2011 and is 17 minutes. But if they're talking about creating 15,000 atoms in a few hours to experiment with then they'd need storage that lasts at least that long.

Lifetime of magnetically trapped antihydrogen in ALPHA

An analysis carried out, using machine learning methods, on more than 1000 antiatoms confined for several hours in the ALPHA-2 magnetic trap, yields a preliminary lower limit to the lifetime of 66 hours. Hence this observation suggests that the measured confinement time of antihydrogen is extended by more than two orders of magnitude.

Antihydrogen Synthesis & Trapping

The lifetime of antihydrogen in the trap seems long (many hours) and mainly limited by the risk of annihilation of the residual gas in the chamber.

[InterestedEngineer]

Antihydrogen Synthesis & Trapping

The lifetime of antihydrogen in the trap seems long (many hours) and mainly limited by the risk of annihilation of the residual gas in the chamber.

That's easy to fix.  Generate enough anti-hydrogen that ALL the residual gas is annihilated.


That might be a way to achieve a more perfect vacuum.

[Twark_Main]

Antihydrogen Synthesis & Trapping

The lifetime of antihydrogen in the trap seems long (many hours) and mainly limited by the risk of annihilation of the residual gas in the chamber.

That's easy to fix.  Generate enough anti-hydrogen that ALL the residual gas is annihilated.


That might be a way to achieve a more perfect vacuum.

I expect launching your thing into space and using the Wake Shield technique is a cheaper way to achieve ultra-hard vacuum than introducing additional anti-hydrogen annihilating into your chain of "vacuum pumps"...

[scienceguy]

For those of you wondering how long an antimatter particle would go before it hits a matter particle and annihilates, it is based on the mean free path. The mean free path is how far a particle will go before it collides with something.

Mean free path of a fast-moving particle in a gas: lambda = 1/((pi)ND^2) where N is the density of the molecules in molecules/cm^3, and D is the diameter of the molecules (McDaniel, 1989, p. 50).

Mean free path = lambda = 1/((pi)ND^2)
If there is only 1 molecule of hydrogen gas per cm^3 (like there is in outer space), then, with a Bohr radius of 5.29 x 10^-11 m, the mean free path of a positron in hydrogen molecules would be
1/(pi)ND^2 = 1/((pi)(1 molecule/cm^3)(1.06 x 10^-8 cm)^2) = 2.83 x 10^15 cm, or 2.83 x 10^13 m or 0.003 light years.

1 light year is 9.46 x 10^15 m. Thus, antimatter essentially does not hit molecular hydrogen in the concentration that molecular hydrogen is in in outer space. Thus, if you have a container for antimatter, it best kept in space.

References
McDaniel, E. W. (1989) Atomic collisions: electron and photon projectiles. Wiley.