Simulation Recipe to Make Matter Out of Light

New simulations by a research team led by UC San Diego’s Alexey Arefiev point the way toward making matter from light. The process starts by aiming a high-power laser at a target to generate a magnetic field as strong as that of a neutron star. This field generates gamma ray emissions that collide to produce—for the very briefest instant—pairs of matter and antimatter particles.

Extreme Light Infrastructure (ELI) high-power laser facilities in Eastern Europe could produce real results in one to two years.

New simulations suggest that by increasing the size of the focal spot and boosting the laser power to around 4 petawatts, the laser’s intensity could remain fixed and still create the strong (1000 Tesla) magnetic field.

Physical Review Applied – Power Scaling for Collimated γ-Ray Beams Generated by Structured Laser-Irradiated Targets and Its Application to Two-Photon Pair Production

SOURCES- UCSD, Physical Review Applied
Written By Brian Wang,

32 thoughts on “Simulation Recipe to Make Matter Out of Light”

  1. That’s true: The key point is that you have to make the field significantly larger than the gyroscopic radius of the incoming radiation, which is a property of both the magnetic field strength and the energy of the radiation. For this purpose a really large, and not particularly strong, field is probably best.

    And forget about the high end cosmic rays, nothing humanly achievable is stopping those, and they’re rare enough to not be worth bothering about anyway.

  2. Thanks. After reviewing the Wikipedia pages for some of those units, it’s just a tad clearer. If out of all of this, I’ll remember to think in terms of flux (and it’s density), rather than some much more nebulous “field strength”, that’d be a win.

    Btw, the SI equivalent of oersted is N/Wb (or A/m), as you probably already know. Which isn’t quite as mystical as “oersted” sounds. It just doesn’t have it’s own name in SI.

  3. PS — all of my astrophysics books, liberated from the defunct-book-pile of my large local library, are in CGS units. 

    The Love of the Erg. 
    Carnal erg pörn. 

    Lobbing around preposterously large orders of magnitude. I mean, mass of stars (☉ = 2×10³⁰ kg, 2×10³³ g, but hydrogen atoms ‘weigh’ 1.66×10⁻²⁴ g, so maybe 10⁵⁷ atoms inside her… 57 orders of magnitude!) and scales of the universe itself … 3.37×10²³ m by light-year-age, but maybe more like 2×10²⁵ or so by expanded baseline age relativism) and so on, well … lots of orders of magnitude. 

    Yet kind of remarkably, almost ALL of it fits inside of 2 digits of powers-of–10 exponents, negative and positive. How blôody convenient!

    Astrophysics before 1970, all CGS.
    After 1980, all rewritten in MKS. 

    Publisher’s dream.
    And the same for post-grads needing to publish. 
    Never let a few orders of magnitude get between friends!

    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  4. PS — all of my astrophysics books, liberated from the defunct-book-pile of my large local library, are in CGS units. 

    The Love of the Erg. 
    Carnal erg pörn. 

    Lobbing around preposterously large orders of magnitude. I mean, mass of stars (☉ = 2×10³⁰ kg, 2×10³³ g, but hydrogen atoms ‘weigh’ 1.66×10⁻²⁴ g, so maybe 10⁵⁷ atoms inside her… 57 orders of magnitude!) and scales of the universe itself … 3.37×10²³ m by light-year-age, but maybe more like 2×10²⁵ or so by expanded baseline age relativism) and so on, well … lots of orders of magnitude. 

    Yet kind of remarkably, almost ALL of it fits inside of 2 digits of powers-of–10 exponents, negative and positive. How blôody convenient!

    Astrophysics before 1970, all CGS.
    After 1980, all rewritten in MKS. 

    Publisher’s dream.
    And the same for post-grads needing to publish. 
    Never let a few orders of magnitude get between friends!

    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  5. Three terms of usefulness, all messed up historically by different units, and loose (wrong-headed) swapping of them at the wrong point of discussion. 

    Weber (Wb), is total flux contained within a magnetic “system”.

    Tesla (T) takes Webers, divides by the area of the core of a magnetic dipole. Wb/m².  This then is ‘flux density’, since “flux ≡ Webers” and “area ≡ unit of density”.  

    gauss has no SI abbreviation, and is one ten-thousandth of a Tesla.  Why? CGS vs MKS … centimeter-gram-seconds versus meter-kilogram-seconds of units. Germany in particular, but also everyone around her in Europe preferred CGS units thru much of Einstein’s revolutionary astro-, nuclear- and relativistic- physics era. America, MKS. SI is now standardized on MKS-for-all.

    Then there are oersteds. No equivalent in SI, a CGS unit of actual magnetic field strength. Very useful for winding transformers and inductors. Lord Maxwell is remembered for the maxwell, unit of webers, but for the CGS environment. 

    As I said, it doesn’t help even a trice that gauss has been loosely use to describe close-field magnetic strength for flexible plastic refrigerator magnets, the Earth, someplace special, or the festively red-and-black painted magnets one can ubiquitously find in any pre-1980s high school physics demonstration laboratory.  There’s your answer, even if it is somewhat opaque! 

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  6. Re the last paragraph, that prob depends what you want to shield against. The higher end of cosmic ray energies is pretty high up. But the energy distribution likely follows a power law.

    edit: Also, size matters, as you point out. A field the strength of a bar magnet but the size of a ship might do; but a field both the strength and size of bar magnet probably won’t help much.

  7. So, 1/r^3 for r much larger than the size of the dipole, seems to be the main take-away. And given the size of Earth and its magnetic source, there isn’t a big difference between surface and LEO. More difference in GEO, I guess.

    Still, what does it even mean when we say “a magnet is X tesla” or “a frdge magnet is Y gauss”? Is that the field at their surface? Or maybe somewhere else?

  8. The electromagnetics lectures at UCBerkely turned out to be vexingly non-intuitive for the magnetic side. Especially when words like ‘magnetic reconnection’ were tossed in, along with ‘field lines’. Both of which turn out to be quantitatively useful, but still fictitious 19th century abstractions.  

    “Earth’s magnetic field strength” is as you surmised: a useful talking-point value, but which is different for all points on Planet Earth. Indeed, a vector having 3 XYZ directionality scalars, or 2 angular scalars and a magnitude (idealized vector length).  That magnitude in Greenwich, England is about ½ gauss.

    The relatively large size of Earth’s dipole means that µ doesn’t drop per 1/r³ from the surface to say LEO. “Up there”, other vexing electromagnetic systems in the local solar wind plasma sometimes add to, sometimes work against the 1/r³ µ-over-distance relationship.  Van Allen belts, solar winds, non-uniform Earth dipole moment, local deep-Earth octopole variations, CMRs (coronal mass ejections(, you name it.  

    However, if we were to shoot a magnetic probe out past Luna, heading ‘straight outward’ (also another convenient fiction), at around 25 Earth radii, the fall-off of µ asymptotically approaches that 1/r³ curve. Until the (1/r³)µ value is on the same order as the magnetic and electrical plasma fields of the interplanetary medium.  

    Sorry couldn’t be clearer.  
    Magnetism is that way.

    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  9. ⊕1 of course.

    At a COI of 6.6 between 1970 and 2020, that $1,500,000 per milligram becomes about $10,000,000 / mg. 

    $10,000 per µg.

    Mayhap I’m full of favabeans, but that STILL sounds like a big economic win. Especially if a competent antimatter catalyzed fusion-or-fission for a 25 ton ♁→♂ shuttle requires only 25 microgram’s worth. 

    $250,000 worth, at the above conversion ratio.  

    Thanks for the ballpark compliment. Every so often, ‘gut feeling’ yields order-of-magnitude useful estimates. Parenthetically, at a tender age (20s) I rationalized that the ∑estimate(i) for (i→large N) becomes ever more accurate if the estimated values maker has no systematic bias either for over, or under-estimation. Turns out to have been a WILDLY successful technique for complex software development project management.  

    Did a huge software development — 1.5 million lines — with a team of 40 and me with my 250 row project plan. I estimated a 8.7 month dev cycle. Was roundly criticized for it by management. We delivered — even with the noise of management’s forced team additions — in 9.5 months. And the software was debugged, wrapped, vetted and in a release-candidate state. 250 rows of ballpark guesses.  

    Did that many times in my professional life. 
    I respect ∑ballparks.

    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  10. Well, to be serious: GoatGuy notes that the field is proposed to be generating in a cubic um, which isn’t going to shield anyone. That’s why it drops off to less than the Earth’s magnetic field so soon. A meter away you’re a thousand field diameters away from the magnet.

    To shield a ship, you’d have to be generating cubic meters of the magnetic field, which, accordingly, would decline in strength much slower, due to scaling effects. And surround the ship with the field, which would be even more effective at maintaining the field strength in the ship.

    The result would be, ignoring the practical impossibility of actually pulling this off, (Which GoatGuy addressed nicely.) a field strength in the ship which would literally directly kill the astronauts. Even at 2T, which is found in MRI machines, you start to see alterations in cardiac rhythms due to inductive effects from motion through the field. At 1000T your heart simply beating would induce enough current to stop your heart. In addition to the fact that the magnetic field would be altering chemical behavior enough that your biochemistry would be disrupted.

    1000T is way overkill for magnetic shielding, anyway. 1T would likely be overkill. The field strengths necessary for magnetic shielding against space radiation are more in the range of what you’d get from a bar magnet.

  11. I think 2% is probably over-optimistic.

    Accelerating the particles to begin with could be highly efficient, say 90%? The real problem is that, while at positron energy levels there’s basically nothing but positrons you can create, there’s lots of garbage you can create at anti-proton energy levels. So the energy gets partitioned between the various possible products, and only a relatively small portion of it ends up as anti-protons. Which then have a fairly high probability of being annihilated before they escape the collision.

    Then you lose a lot of the energy slowing the anti-protons down again, and cooling them is energy intensive.

    I found the analysis I’d once read of an accelerator optimized for just producing antimatter. The estimated cost, back in the 80’s, was about $1.5 million per milligram.

    You arrived at a quarter million per milligram. Actually pretty close for just ballparking it.

  12. In another sub-thread, GoatGuy commented that this would be weaker than Earth’s field just 1m away. Are you guys mixing terms? Or adding hidden assumptions that change from comment to comment? Perhaps about the size of the field source?

  13. So when you say Earth’s magnetic field is 10 gauss, which altitude is that at? Sea level? What about at LEO or GEO? If it doesn’t drop off just as fast, why is that?

    I’ve found it confusing for a while now, that magnetic field strengths are listed as just an absolute number, with no regard for the distance from the source. Obviously it’s not a constant in space. And it’s not exactly the magnitude of some “magnetic charge” either, right? What am I missing?

    edit: To sharpen my question, with electrical fields, we can talk about charge magnitudes in culoumbs and voltages in volts, and then we say “the field at X distance from source with Y geometry and this or that charge or voltage is Z”. But with magnets, we seem to just say “this magnet is X tesla strong”. But tesla is a field strength unit, and that changes with distance, doesn’t it? It doesn’t make sense.

  14. It IS a nice paper.
    It’s not that often that you are reading a serious document with the line

    the Sun is not energetic enough

  15. E=mc^2.
    Meaning a very, very large amount of E is needed to make a very, very small amount of m.

    You’d be better off catching the hydrogen ions in the solar wind, than catching the solar light and turning it into hydrogen.

  16. OK, i’ll bite.

    Is it asking too much for a purpose-built machine to convert energy → antiprotons and antielectrons at an efficiency of, mmm… 10%? Maybe too much.  At the outset, at least 50% is probably lost to protons and electrons, normal kind.  

    OK, 2% then. It could be any number. 

    The Bickford paper cites that only a handful of micrograms would be enough to cut the ♁ → ♂ transit from 180+ days to maybe 50.  A mere whiff of antimatter and a bunch of other stuff that can be catalyzed into fissioning or fusing. Or both.  And all that. 

    10 micrograms.  
    E = mc² … in MKS SI units
    E = 10×10⁻⁹ kg × 299,792,458²
    E ≈ 1 GJ in round terms.

    At 2% efficiency, that’s an input of 50 GJ.  
    Heck, only 14,000 kilowatt hours of energy IN.
    At 18¢/kWh, that’s $2,500 in pocket change.

    Not 2.5 million, or 2½ billion bucks.  Just a monthly house payment in an ordinary part of Cincinnati. 

    My math must be off. 
    Or not.  But if its ON, it sure sounds good. 
    Even if it were off by a factor of 1,000 … its still not bad.

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  17. I would mention that, while the wall socket efficiency of modern particle accelerators for producing antimatter is horrifically low, that’s in no small measure because they’re designed to manufacture scientific papers, not antimatter. A particle accelerator specifically designed for no other purpose than antimatter production could be several thousand times more efficient.

  18. Yah, fading memories have loose orders-of-magnitude. You’re probably right. 10 micrograms a year per satellite sounds far more reasoned.  

    Just catching 10 mg a year begs “how would it be stored long enough to be used”.

    Blikford’s paper is nothing short of excellent. Thanks again for the linkie.

    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  19. If you could get their machine to generate only protons anti-protons pairs…. then you could just apply a static electric field between the two particles and pull the protons to the negative terminal and the anti-protons to the positive terminal… then all you need to do is throw in a few electrons on the proton side, and throw in a few a positrons on the anti-proton side,,,, now, you have successfully created hydrogen and anti hydrogen atoms… the hydrogen you save to make water… the anti hydrogen you save to use as rocket fuel by annihilating it..

  20. Now if they can figure out how to make hydrogen from light… that’s a recipe for colonizing mars….

  21. Yep. I was thinking BECs , as they seem uniquely able to live for great lengths of time suspended in magnetic-electrical-photonic field traps.  

    Still, wasn’t there a proposal to collect up to a kilogram of antimatter from the Van Allen belts of good Ol’ Earth? (per year, fleet of collectors, ‘high’ enough to have perpetual non-decaying orbital characteristics)

    Bose Einstein Condensates are special. 
    Another state of matter.

    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  22. Positrons are fairly easy to produce. The real goal here is producing anti-protons efficiently, (Less than 50%, obviously, because you’re making protons at the same time.) because without anti-protons, you can’t really store anti-matter at a high enough density to be worth it, thanks to space charge problems.

    Once you’ve got anti-protons, you can generate anti-hydrogen, which can potentially be stored in the solid state at very low temperatures, allowing much higher energy density than fission or fusion provide.

    I suppose if unicorns are made of antimatter, it explains why nobody has seen one.

  23. Yah, and unicorn horn dust, at the same time. It being somewhat MORE valuable, especially in solving nearly unsolvable sub-luminal spacecraft speeds. Unicorns beat antimatter ANY day! Saith The Goat…

  24. Yes, and for added protection there is the 1/r³ scaling of poloidal magnetic fields.  The geometry of this is what, tens of µm?  

    25×10⁻⁶ m.  

    So, at 1 m, the magnetic field of a 10,000 T magnet field would be 

    10,000 T • (25×10⁻⁶)³ / (10⁰)³
    ≡ 0.00000015625 T
    ≡ ¹⁄₆₄₀ gauss

    Your common not-very-strong-but-free! refrigerator magnet has a near-field magnetic field strength of, oh, about 10 gauss, and the Earth’s very own magnetic field is about ½ gauss.  

    So, ¹⁄₃₀₀ of earth’s magnetic field strength, at 1 m.  

    Not very much. Rather small, actually.  Basically almost unmeasurable without superconducting SQUID devices. Well below Hall Effect sensors. Maybe in the realm of Colossal Magneto-Resistive doohickeys. You know, the itsy-bitsy bits mounted on spinning hard disk read heads to detect those gigabits-per-second at many GHz rates!

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  25. Apart from the ⊕1 Brett Bellmore comment, the ‘other problems’ are that the generating scheme uses petawatt lasers (№ 1) focussed into volumes of cubic µm (№ 2), which are (10⁻⁶)³ m³ or 10⁻¹⁸ m³ in volume.  

    Given that you, me and our oxygen tanks IN a big ol’ tin can whizzing at near ‘c’ speeds (let’s be hopeful!) are substantially larger than 10⁻¹⁸ m³, and more like 15² radius • π × 100 m long, or 80,000 m³, then that magnetic field would have to be sized up by, oh, 80,000 ÷ 10⁻¹⁸ → 10²³ times.

    10,000,000,000,000,000,000,000 ×.  

    And a petawatt is 1 with hmmm… kilo = 3, mega = 6, giga = 9, tera = 12, peta = 15? zeros.  

    10²³ × 10¹⁵ → 10³⁸ or 100,000,000,000,000,000,000,000,000,000,000,000,000 ×

    I guess my question would be, who the heck is going to build this laser, AND, how do they propose to project its magnificent energy those bazillions of kilometers as our intrepid space can whizzes to the next star?

    Putting 10³⁸ W in perspective, the output (entire) of the SUN in all directions is about 3.8×10²⁶ W. So, this laser need only be 1 TRILLION times the output of the Sun. Each second of operation uses more power than ALL of the Sun’s output … in 10,000 years.  

    Ah, the powers-of-ten, and how daunting they are to realize. Even tho’ we math folk can throw around scales from cubic nanometers to a gazillion times the size of the universe in a few unsuspecting ‘e’ numbers. 

    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  26. It would be strong enough to kill the astronauts itself, so the shielding effect would be kind of moot.

  27. So there is no risk in creating such strong magnetic field.
    Just asking because i dont want wiped harddisks, or medical devices to fail…

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