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New Accelerator Technique Doubles Particle Energy
ZonkerWilliam writes "Plasma wake particle accelerators are making surprisingly quick advances. It was a just a little while ago we had GeV acceleration in 3cm. Now they are capable of doubling the energy of electrons. 'Imagine a car that accelerates from zero to sixty in 250 feet, and then rockets to 120 miles per hour in just one more inch. That's essentially what a collaboration of accelerator physicists has accomplished, using electrons for their race cars and plasma for the afterburners. Because electrons already travel at near light's speed in an accelerator, the physicists actually doubled the energy of the electrons, not their speed.'"
OMG teh fasterzorr elektrons! LOL more FPS!!!!
One of these days those crazy scientists are going to do something and we will all just disappear into a mass of energy.
in 5, 4, 3, 2, 1...
(I feel that in a public forum like this it's reasonable for people to call upon me to justify my statements. But this statement is so completely ridiculous that I hardly even know where to start justifying myself.)
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
The kinetic energy is proportional to speed^2 (E=1/2 m v^2), so a car at 120mph has 4 times the energy of a car at 60mph. Thus, doubling in energy is not like doubling in speed.
Wouldn't rocketing a car from 60 to 120 quadruple the car's energy? A better analogy might be that it's like rocketing the car from 60 to 85.
If I think something is funny, I will probably mod it +1 Insightful. "It's funny because it's true."
Unfortunately, these concepts will not be applied to the next generation of high energy accelerators. The International Linear Collider will supplant the Large Hadron Collider some time after 2015, but relies on superconducting static-gap technology and will be 30-40 kilometers long. Perhaps the next generation of experiemnts will employ plasma accelerators?
You might not believe it but there are some bona-fida scientists skulking about slashdot.
That's essentially what a collaboration of accelerator physicists has accomplished, using electrons for their race cars and plasma for the afterburners.
Those sound like really small physicists.
Wizard Needs Food, Badly
still stands though, 120 mph would be 4 times the kinetic energy of 60 mph.
If I think something is funny, I will probably mod it +1 Insightful. "It's funny because it's true."
From the article description: 'Imagine a car that accelerates from zero to sixty in 250 feet, and then rockets to 120 miles per hour in just one more inch.
Say hellow to jello bones.
SJW: a person who perceives an injustice, and while correcting it, commits a greater injustice.
In terms of solving the relevent math covered in the study of Quantum Mechanics and Molecular Spectroscopy (senior Inorganic Chem II at my alma mater), pumping energy into an electron is computationally similar to accelerating an object of 1000 kg mass to 60 mph over the span of time required to travel 250 feet and then nearly instantaneously pumping enough energy to double the velocity in the span of time represented by the distance travelled in one more inch.
the NPG electrode was replaced with carbon blac
Forget portable cancer treatments, I want to bust some ghosts. Or at least get paid to blow the crap out of a fancy hotel. Never mind the part about it still needing two miles of pre-acceleration before the plasma wakefield thingamabobby kicks in, that's just a minor hiccup. Proton packs are just around the corner.
Ahhhh, I love the smell of burning ectoplasm in the morning! It smells like victory.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
E=mv^2/2 only for small values of v.
The other formula for E, you might have heard of, is E=mc^2. m = \gamma m_0, where m_0 is the rest mass, \gamma = 1 / sqrt(1 - \beta^2), and beta = v/c. I.e.,
E=m_0 c^2/sqrt(1 - v^2/c^2)
For very small values of v (relative to c), 1/sqrt(1-v^2/c^2) \approx = (1/2)v^2/c^2, which leads back to your formula - but the approximation is only valid for v
Ben Hocking
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I assume you are referencing Dimopoulos and Landsberg's paper http://prola.aps.org/abstract/PRL/v87/i16/e161602 . There is nothing to worry about. These physicists proposed that if certain theories were true (M theory, quantum loop gravity, super symmetry) then the energy densities seen in the RHIC or LHC experiments could produce something "mathematically analogous" to a black hole. There is no possibility under any current theory that an event horizon could form and attract matter.
I jammed a butter knife into a 220v circuit when I was a toddler and became a diembodied electromagnetic life-force with super powers.
Other than a morbid fear of lightning rods and antistatic wrist-straps, it pretty much rocks.
In my day, we just banged rocks together! And we were grateful!
-jcr
The only title of honor that a tyrant can grant is "Enemy of the State."
1/2 mv^2 is the non-relativistic kinetic energy. The mass correction will change the energy rapidly as v approaches c. The mass correction with the Lorentz factor in that expression are needed to get the correct relativistic energy.
The lorentz factor is 1/sqrt(1-(v/c)^2); at 0.99c it will multiply the mass (and energy) by a factor of 7; at 0.999c it will multiply everything by a factor of 22.3.
They increased the mass of the electrons by 1.65064935 × 10-27 hundredweight in 0.00032808399 football fields. Sorry, I don't know how much that is in SUVs.
Seriously, though, this is a neat trick. (Yes, IAAP)
Now they are capable of doubling the energy of electrons.
Does it involve teeny-tiny little cans of Red Bull?
Cue the crackpots who deny the science.
Unless you can explain that to me in terms of volkswagens, elephants, and libraries of congress, I'm afraid you've lost me there. P.S. Giving scientific notation to the average American is like giving a speak and spell to the average ant. They can't even press the buttons. Besides, only engineers use decimal measurements, everyone else uses fractions.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
'Imagine a car that accelerates from zero to sixty in 250 feet, and then rockets to 120 miles per hour in just one more inch. First of all at non relativisitc speeds, doubling the speed results in a four fold increase in kinetic energy and not a doubling. Why give a bad classical mechanics analogy and then tell us that the speed didn't actually double because of relativistic effects.
I actually do some work on this with the PWFA group at USC (i'm an undergrad research assistant). It really is amazing! We can reach acceleration gradients of around 60 GeV/m, compared to something like 40 MeV/m for a normal accelerator. It works like this: .or at least something close to that!
1. The electrons travel down the main linac in carefully spaced "bunches", and get accelerated to around 43 GeV over a course of ~3KM (this is at the main beam at SLAC).
2. A (in the last experiment) 1.2m long Lithium plasma "oven" is at the end of the beam, which the electrons are directed into.
3. The first, or "driving," bunch goes through the plasma, and repels all of the electrons it gets near, leaving an "empty" wake behind it, where only the positively charged ions are.
4. The positive charge behind the driving beam pulls it backwards, causing it to lose energy. At the same time, a "witness" bunch placed strategically within the wakefield gets pulled forward by the positively charged ions. The witness gains energy while the driver loses energy.
5. Voila! One bunch now has twice the energy, and one bunch now has none . .
The main caveat is that you're upward-limited by your entering energy, so you still need a huge Linac to accelerate the bunches to begin with. This will likely get tacked on in the form of a "plasma afterburner" to a normal linac, such as in the setup at SLAC.
I'm perfect in every way, except for my humility.
As I understand it, luminosity is one major reason why this technology is not yet ready for prime time (i.e. not in time for the proposed ILC). You can't just accelerate a few particles to high energies and say you are done. You're looking for rare processes, so you need to create many consistent particle collisions per second in a tiny area. This means you need to have a tight, "bright" beam. The Tevatron has a luminosity of ~2e+32 interactions/cm^2/s now, the LHC may eventually reach 1e+34, and the goal for the ILC is more like 2e+34. Plasma wakefield systems are now demonstrating large increases in energy over short distances, but it's very difficult to daisy-chain them together to reach high total energies with any significant luminosity.
Imagine a bunch of cars that accelerate from zero to sixty in 250 feet, then slam into a barrier, causing a multi-car pileup from which, starting just one inch further down the road, one of them rockets out at 85 miles per hour.
(Obviously they were inspired by the traffic on Interstate 280 on their way to SLAC. B-) )
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
A simple, easy to understand explanation of the phenomenon in layman's terms! So basically they're using the plasma to transfer energy from one group of electrons to another group of electrons... why couldn't the original article say that?
Hmm. Well which is it, are we doubling velocity or engery? I'm no rocket surgeon, but I'm pretty sure these are different things. If it's energy then I think the analogy should have been, "...and then rockets to 85 miles per hour...".
But I guess that doesn't sound as cool...
does anyone ACTUALLY care about this? slownewsday
\.
Rushed through it too quickly.
Ben Hocking
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"it could be bad"
Any black hole created in a lab on earth is going to have negligable sucking power, since the mass in them will be tiny. The vision of a black hole forming and swallowing the earth is great sci-fi, but (happily) poor science. At worst, it will hang around, swallowing the odd electron at very rare intervals.
Wikileaks, no DNS
Cue people who pretend they understand the science...
As mentioned, there are some of us around here who are actual scientists. However, there are no details in the article, thus no science to understand. All I found were crappy analogies with afterburners and some hand-wavey crap about plasma. I'm pretty sure that if it were as easy as running some crap through a plasma to accelerate it, it would have been done some time ago. And there are a number of pertinent questions:
Why do they have to use a 2-mile accelerator if the plasma can do in a foot what it takes the 2 miles to do?
Why can't it be longer?
How is the plasma chamber set up? I'm guessing it's probably an coupled with an RF field, which can accelerate a plasma, but details, come on!
wow, you're good.
Is this going to improve my 3d graphics accelerators?
You are right. It's been a while since I've delved into relativity (I'm embarrased to admit that my Master's thesis involved general relativity). The complete equation for energy, including rest mass and kinetic energy is:
E = sqrt(mc^2 + pc),
or as it's more commonly written:
E^2 = (mc^2)^2 + (pc)^2,
where m is the rest mass. Speaking of general relativity, I should point out that the above equation for energy is assuming a Minkowski (flat) space-time metric.
Thanks for the correction.
True. However, for v significantly smaller than c, 1/sqrt(1-v^2/c^2) approaches 1 + (1/2)v^2/c^2 + (3/8)v^4/c^4. For even smaller v, you can drop the v^4 term and get 1 + (1/2)v^2/c^2 which does yield E = mc^2 + (1/2)mv^2, which is why it's easy to make the mistake that I made. (Obviously, for even smaller v, this does approach mc^2, but that's similar to saying that kinetic energy is insignificant relative to rest energy. I say similar, because I'm also not claiming anymore that my original equation was right - just an interesting, if misleading, approximation.)
Ben Hocking
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Maybe it's a good thing the US _didn't_ sink all that money into the Superconducting Supercollider; or build our own LHC. If plasma wake accelerator technology keeps improving, we may yet build an accelerator that powerful for a lot less money.
http://en.wikipedia.org/wiki/Plasma_acceleration
I seem to recall an article in either Nature or Popular Science late last year. Interesting article, had the physics explained well for even the most obtuse of science enthusiasts. If I recall correctly, it involved a jet of plasma that the electrons were streamed through, with the output pattern similar to optical magnification. Oddly, from the diagram it appeared that the jet was perpendicular to the electron stream.
~ Kylu
All your electron-Volts are belong to us.
Only Old North Koreans need souped up particle accelerators.
In Soviet Russia, particles accelerate YOU!
What did I forget?
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THAT has to be the most lucid and helpful explanation of a simile that I have EVER seen. It had always been explained to me as: a comparison that used "like" or "as". So entirely inadequate compared to your definition and examples. As someone who actually enjoyed studying grammar and who is also a bit of a wordsmith, you've filled in a great gap in my understanding. Thank You!
I took a quick look at Wikipedia's definition of simile -- it's the same old inadequate explanation I'd been taught. PLEASE, PLEASE, PLEASE upgrade their defintion of simile with yours!!! (I'd do it myself, but you deserve the credit.)
If the collimated beam going into the plasma chamber gained a bunch of energy (42GeV) in the space of 84cm, that means total time of flight in the chamber was in the nanosecond range. That means a jillion collisions with the plasma. Wouldn't this screw up the focus of the beam? Sure, you've got a more powerful pulse of electrons coming out, but they will be sprayed all over the place, so the amount of energy that you can put into your incoming target beam of positrons (or into a stationary target) is diluted, isn't it?
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Based on the document the device probaply works in a way that an electromagnetic wave beats up the spead. Acoording to the article and some pubolcations of the LHC not all the input catches it's flight on those waves. This results in spreading of those particles, spreading in spead/energy/beam overall its not delieverd as how those particles run trough exactly timed intervals in a focussed way as in the currently operative LHC. The spreading gives the output a randomnes which i gues, a lot of scientist would not like to see Man they repeat experiments lots of times and hope for that little change to see something and retry it again and again to get a statistical propability that their measurments are ok... This device is a bit like an uncontroled afterburner, altough that's still quite an acomplishment. This spreading is probaply the reason why it cannot be made much more longer then that. But who knows perhaps later they put such a device in large on the LHC too, who knows..
I know you're out there. I can feel you now. I know that you're afraid. You're afraid of us. You're afraid of change.
If you accelerate from 0-60 in a car, then double the kinetic energy, you are now not going 120. It's closer to only 84.
Remember, e=mv^2, so for a constant mass, the velocity only increases as the square root of the engergy.