Personally, I think this has to do with thunderstorms being essentially linear accelerators, vertical SLAC’s if you will. Huge charge differentials from top of cloud to bottom makes for a nice particle slingshot. There’s plenty of opportunity for antimatter (positrons) to be created in energetic collisions from particles coming out of the tops of thunderstorms. Sprites and blue jets for example, may be indicators for energetic particles.
It could also be very energetic photons from lightning as seen in the diagram below. At the high photon energies (twice the rest energy of electrons at 511 keV) and above 1.022 MeV positron-electron pair production may take place. Getting energies of 1.022 million electron volts certainly seems easy enough in thunderstorms. – Anthony
From Sciencenews.org: Signature of antimatter detected in lightning
Fermi telescope finds evidence that positrons, not just electrons, are in storms on Earth
Washington — Designed to scan the heavens thousands to billions of light-years beyond the solar system for gamma rays, the Fermi Gamma-ray Space Telescope has also picked up a shocking vibe from Earth. During its first 14 months of operation, the flying observatory has detected 17 gamma-ray flashes associated with terrestrial storms — and some of those flashes have contained a surprising signature of antimatter.
During two recent lightning storms, Fermi recorded gamma-ray emissions of a particular energy that could have been produced only by the decay of energetic positrons, the antimatter equivalent of electrons. The observations are the first of their kind for lightning storms. Michael Briggs of the University of Alabama in Huntsville announced the puzzling findings November 5 at the 2009 Fermi Symposium.
It’s a surprise to have found the signature of positrons during a lightning storm, Briggs said.
The17 flashes Fermi detected occurred just before, during and immediately after lightning strikes, as tracked by the World Wide Lightning Location Network.
During lightning storms previously observed by other spacecraft, energetic electrons moving toward the craft slowed down and produced gamma rays. The unusual positron signature seen by Fermi suggests that the normal orientation for an electric field associated with a lightning storm somehow reversed, Briggs said. Modelers are now working to figure out how the field reversal could have occurred. But for now, he said, the answer is up in the air.
Recording gamma-ray flashes — which have the potential to harm airplanes in storms — isn’t new. The first were found by NASA’s Compton Gamma-ray Observatory in the early 1990s. NASA’s RHESSI satellite, which primarily looks at X-ray and gamma-ray emissions from the sun, has found some 800 terrestrial gamma-ray flashes, Briggs noted.
Kevin Kilty (09:30:42) :
Sorry Kevin… I wasn’t referring to your comment, but the above diagram:
http://go2.wordpress.com/?id=725X1342&site=wattsupwiththat.wordpress.com&url=http%3A%2F%2Fupload.wikimedia.org%2Fwikipedia%2Fcommons%2F8%2F84%2FPairproduction.png
Some great comments everybody!
This is the significant phrase:
“The17 flashes Fermi detected occurred just before, during and immediately after lightning strikes, as tracked by the World Wide Lightning Location Network.”
Distributions always have tails, and there are many distributions entering the problem. They are talking of a few hundred gamma rays and 17 positron signatures.
If I were writing the Monte Carlo program I would need a number of distributions, but I am sure I would be able to get, out of the trillion possibilities of phase space, 17 electron positron events.
Now you just need to work out how to channel 1.21 gigawatts from that lightning strike into your Flux Capacitor…..
anna v (11:25:07) :
Kevin Kilty (09:46:42) :
First lets see where one can get the gamma rays.
There are electrons around nuclei and obviously since thunder storms have high electric fields they are spinning around , as well as the stripped nuclei as ions.
1) The direct energy input is via electrons accelerated by the electric field. So, we must go from accelerating electrons to braking them (bremstralung), creating a photon, then having the photon collide with another nulceus and produce a particle pair.
2) Suppose the photons can be produced in the fist place. Up to an energy of about 10Mev these photons are involved in Compton scattering, above 10Mev or so they produce particle pairs.
3) So our electron acceleration has to produce several MEV anyway. But as I pointed out very early in this thread the atmosphere even at 100km is not thin enough to allow an electron to accelerate to several MEV (in a field of 1 million volts per meter the electron would need a free path of 1 meter to reach 1Mev). What is the free path length at 100km? I dunno, not one meter I’ll bet, and down in the region of lightning it is next to nothing.
So, I suggested maybe there are other mechanisms, and Luboš Motl (11:00:51) suggests that there are positrons around in the air anyway, and the lightning interacts with them in some way. Suppose we can get some positrons from Carbon 14or Nitrogen 13?
Here is another possibility. What if materials in the detector itself has a few decays now and then and produces the requisite positrons itself now and then. Look 17 gammas is such a low signal it could be randomness mascarading as signal, yes?
Let me clarify. Maybe we can get positrons from the gammas produced with Nitrogen 13. Carbon 14 produces no gamma, but there are always cosmic rays around.
tallbloke (10:37:03) :
Ha! It pays to check the sources. I thought the Pontifical Council for Justice and Peace conference was current until I checked Gene Nemetz’s link for Antonino Zichichi’s quote.
Sorry, but that conference couldn’t have taken place in 2007- the “Consensus” was in effect.
yonason (09:58:44) :
Love it – Seth Putterman and colleagues at the University of California, Los Angeles (Nature 455 1089) applying for a portable x-ray generated by sticky tape!
Seth Putterman and colleagues at the University of California, Los Angeles (Nature 455 1089) applying for a portable x-ray generated by sticky tape PATENT!
supercritical (11:19:43)
asked about cosmic rays and lighting?
Apparently that’s not so far fetched.
http://www.scientificamerican.com/article.cfm?id=experts-do-cosmic-rays-cause-lightning
“Decades of electric field measurements made inside thunderstorms have failed to find large enough electric fields to cause a spark, even when the effects of precipitation are taken into account. Since we know that lightning does occur—in fact, it strikes the earth about four million times a day—we must be missing something in our understanding.”
Apparently it might work like spark-gap detectors, where the particle shower resulting from cosmic particles entering the atmosphere “might provide a conductive path that initiates lightning”
“”” Kevin Kilty (09:30:42) :
I suppose if we want to be very correct about what people observe here, the picture of a gamma just coming sufficiently close to a nucleus is not right. The researchers are observing not the positrons themselves, but the gamma rays characteristic of a positron annihilating an electron. The two masses in such a collision effectively vanish and the energy, momentum, and parity of the original particles is carried away in one, two or three emitted gamma rays. The instruments detect gamma rays with 0.511Mev energy and the scientists infer that positrons are present.
So where do the positrons come from? If an electron can be accelerated to at least 1.022Mev, as Anthony says, there is enough energy to create an electron, positron pair. However, this is a bare minimum requirement. There must be other particles involved in order to explain the sudden appearance of a unit of positive charge. “””
There really isn’t any sudden appearance of a positve charge; the Positron/Electron pair are generated at the same time so there is no unbalance of charge generated. Presumably the positron and electon would fly off in opposite directions, so eventual anihilation of the positron, is not simply a recombination with its mirror image; they should never meet again.
There was a time I could have told you the origin of the pair; but too much water has probably gone under the bridge.
Anna v. probably can tell us where the pair comes from.
When I was at the university; we used to wait patiently for a good thunderstorm so we could go down to the harbor, and launch a hydrogen filled weather (radiosonde) balloon carrying an electronic system to measure the electric fields under the thunderclouds; well you don’t think we could afford to buy Helium, do you ? So far as I know, we all survived, and never got ourselves either zapped or hydrogenated. But this was all low altitude work; so not a chance of getting a mean free path long enough to get to the 1.022 MeV pair production threshold.
Now here’s something interesting.
http://astroparticle.uchicago.edu/DMfest/jd.pdf
It appears to be along the lines of what the SciAm paper discussed, and on page 8 we find “Relativistic Air Breakdown Due To X-Ray and Positron Feedback.”
Hmmm, have they actually measured that, or just modeled it? Looks like data from an experiment, perhaps?
OK, it’s going to take a bit to go through this next one, but it looks interesting, especially the bit about positrons on p.38, bottom left and continuing in right hand column.
http://www.phy.olemiss.edu/~jgladden/phys510/spring06/Gurevich.pdf
Any thoughts?
***********************
George E. Smith (16:26:05) :
There really isn’t any sudden appearance of a positve charge; the Positron/Electron pair are generated at the same time so there is no unbalance of charge generated. Presumably the positron and electon would fly off in opposite directions, so eventual anihilation of the positron, is not simply a recombination with its mirror image; they should never meet again.
*******************
But any positron would quickly find another electron somewhere and be annihilated.
“”” yonason (16:18:09) :
supercritical (11:19:43)
asked about cosmic rays and lighting?
Apparently that’s not so far fetched.
http://www.scientificamerican.com/article.cfm?id=experts-do-cosmic-rays-cause-lightning
“Decades of electric field measurements made inside thunderstorms have failed to find large enough electric fields to cause a spark, even when the effects of precipitation are taken into account. Since we know that lightning does occur—in fact, it strikes the earth about four million times a day—we must be missing something in our understanding.”
Apparently it might work like spark-gap detectors, where the particle shower resulting from cosmic particles entering the atmosphere “might provide a conductive path that initiates lightning” “””
I’m not so sure that that is surprising Yonason. I’ve seen plenty of cloud to ground strikes; I used to chase them in St Louis Mo. And I have flown over enough midwestern thunderstorms (wall to wall) and watched cloud top strikes from one cloud to another.
The point is that these lightning strikes are not “in the cloud”, but are from cloud to ground or cloud to cloud. I suspect that thunderclouds are likely to be conductive enough (at relatively low fields) to be essentially closed conductors; which does not stop the cloud from building up a very large charge; but the Biot-Savart law would prevent fields inside a closed conductor; and presumably severely limit the field inside a weakly conductive body; so one would not expect spark discharges to occur inside the cloud; but eventually you can get enough charge on the cloud to get a zap to ground ( or whichever way they say the zap currently goes).
I knew at one time what the limit fields were that they generated inside the tube of the Stanford Linear Accelerator (in a vaccuum). We studied the design details of the original 220 ft prototype, that they made before the 2 mile long full sized machine was built. The whole accelerating tube was made of OFHC, and the microwaves that were injected into that, to create the wave that the electron ride on, were limited in power by the maximum electric field that the thing could stand, before it started peeling stuff of the copper. I’m thinking that was somewhere around 3 MV/cm; but it might have been 3MV/m, which seems somewhat puny to me. I think X-ray Linacs run in the fractional MV/m range.
As to what finally trips the cloud discharge in the lightning case; it very well could be cosmic ray trigegred but I don’t know that for sure; in fact not sure enough to even say that’s my opinion. But inside the cloud zapping seems a no0no to me, because of Biot-Savart.
Quoting:
“1.022 million electron volts certainly seems easy enough in thunderstorms.” – Anthony
Comment:
Well, I remember hearing somewhere that a single bolt of lightning can produce as much as 1.21 Jigawatts. 😉
George E. Smith (16:50:02) :
Are you taking their “inside thunderstorms” to mean “inside clouds?” Because I thought they meant the whole environment in which the storm, i.e., the discharge, took place, from ground to cloud and/or between clouds.
I don’t know enough of the details. I’m just looking for potentially reliable sources around keywords lightning, positron, “cosmic ray” and then with the primary authors I snagged in the fist search.
Did you see my yonason (16:39:01) ? Because they get into the theory, including some of the physics and what the numbers should and do look like. With your experience, you sound like you are more equipped to pick up on what they are saying faster than I am. I would have copied what I thought were some relevant comments, but my mouse isn’t working (right click is dead).
“”” Jim (16:46:52) :
***********************
George E. Smith (16:26:05) :
There really isn’t any sudden appearance of a positve charge; the Positron/Electron pair are generated at the same time so there is no unbalance of charge generated. Presumably the positron and electon would fly off in opposite directions, so eventual anihilation of the positron, is not simply a recombination with its mirror image; they should never meet again.
*******************
But any positron would quickly find another electron somewhere and be annihilated. “””
“””” so eventual anihilation of the positron, is not simply a recombination with its mirror image; they should never meet again. “”””
Did you read that Jim ?
Of course anihilation of a positron happens when it encounters an electron; I simply said that electon that anihilates along with the positron, is NOT the electron generated along with the positron, because they fly apart in opposite directions.
As for positrons sitting around in the atmosphere; I doubt it; there’s far too many free electrons always, for any isolated positron to exist for very long.
I don’t know about everybody else; but I’m afraid that when somebody tells me that anti-matter is being generated, I do NOT think of electron/positron pair production in that context (even though I do agree that positrons are anti-matter.
Pair production from MeV plus photons, as described by Anna.v is so common; that is is hardly something to write home about.
In my mind it is akin to saying that polar bears are dying up in the arctic from lack of ice.
When you find some anti-protons or something even weirder flying around the clouds; then give me a shout; but positron/electron pair production is not woth the phone call.
“Using very low frequency (VLF) wire antennas that look like clotheslines, Price and his team monitored distant lightning strikes from a field station in the Negev desert. Observing lightning signals from Africa, they noticed a strange phenomenon in the lightning strike data – a phenomenon that slowly appeared and disappeared every 27 days, the length of a single full rotation of the sun. “We noticed that this bouncing was modulated by the sun, changing throughout its 27-day cycle. The variability of the lightning activity occurring in sync with the sun’s rotation suggested that the sun somehow regulates the lightning pattern.” ”
http://www.jpost.com/servlet/Satellite?cid=1257455212868&pagename=JPost%2FJPArticle%2FShowFull
It seems like the more we learn the more we realise how much we don’t know.
“surprising” “puzzling findings” “It’s a surprise”
What sensible reason is there to be surprised to learn that there are things we did not know?
Furthermore, what advantage is there in admitting (publicly) to lacking imagination?
Very amusing.
Just The Facts (19:27:28) :
“We noticed that this bouncing was modulated by the sun, changing throughout its 27-day cycle.
Thanks for the link, I will be following this one with real interest. If we find an accurate way to measure solar rotation it will answer many questions.
A link to the solar rotation paper using VLF can be found here:
http://www.tau.ac.il/~royyaniv/ILAN_website/solar.pdf
Re: Geoff Sharp (21:08:56) & Just The Facts (19:27:28)
thank you — interesting
Just The Facts (19:27:28)
Nice Find!
If we look at the image provided with this post with the exotic elves and sprites, if there is an accelerator phenomenon it would be there with the fields at the top where the density is very low, no? I am trying to find an open link for a table or figure of density versus height in the atmosphere unsuccessfully .
As for positrons existing transiently anyway, it is true, from decays of isotopes of gasses, but why would they concentrate where the lightening strikes in order to create bursts? Sounds more difficult to find a mechanism than an acceleration phenomenon.
There could be a lot wrong with this, but it suggests that the production of anti-matter reactions is not all that hard. Kind of like Christopher Lloyd dancing around in the 1960’s shouting 1.21 gigawatts:
Maybe our first star ship doesn’t have to wait until the 23’rd or 24th century. Maybe we don’t all have to become subsistence farmer/peasants in the 21st century.
George E. Smith (16:26:05) :
I was speaking at 9:30 of direct conversion of electron KE to the pair of particles. See my 15:30 post about why it is unlikely we can get electrons to a few Mev in the atmosphere.
I don’t think lightning does this directly…something else is up.