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New Accelerator Technique Doubles Particle Energy

ScuttleMonkey posted more than 7 years ago | from the double-your-pleasure dept.

Science 124

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.'"

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124 comments

OMG FP (1, Funny)

Anonymous Coward | more than 7 years ago | (#18017118)

OMG teh fasterzorr elektrons! LOL more FPS!!!!

We're all going to die! (4, Funny)

BagMan2 (112243) | more than 7 years ago | (#18017126)

One of these days those crazy scientists are going to do something and we will all just disappear into a mass of energy.

Re:We're all going to die! (1)

purpledinoz (573045) | more than 7 years ago | (#18017194)

There's talk about creating mini black holes with the upcoming particle accelerator coming online in a few years (I don't remember what it's called). But apparently, these mini black holes will evaporate very quickly, so there's no danger in creating a black hole that will go out of control. I hope they're right.

Misunderstanding (5, Informative)

erosannin (898004) | more than 7 years ago | (#18017330)

I assume you are referencing Dimopoulos and Landsberg's paper http://prola.aps.org/abstract/PRL/v87/i16/e161602 [aps.org] . 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.

Re:Misunderstanding (0)

Anonymous Coward | more than 7 years ago | (#18017408)

Conclusions about theories based on other theories. Physicists attempt to mathematically model the universe -- no mathematical model is entirely correct.

Just because no human being has yet conceived of the possibility doesn't mean that the possibility doesn't exist. To believe so would be to demonstrate supremely dangerous arrogance.

Re:Misunderstanding (3, Insightful)

andy314159pi (787550) | more than 7 years ago | (#18017470)

What if D-O-G really spelled C-A-T

Re:Misunderstanding (0)

Anonymous Coward | more than 7 years ago | (#18017668)

Then cat would refer to both cats and dogs? I don't see what your point is, unless again, you're one of the types who tends to believe religiously in physics theory as if it's already solved every problem in the known universe. It hasn't.

Really, if that was an attempt to refute my point, it was a pathetic one.

Re:Misunderstanding (0)

Anonymous Coward | more than 7 years ago | (#18019066)

His point was that your "point" was vaccuous.

Old Chestnut (2, Informative)

Morosoph (693565) | more than 7 years ago | (#18019072)

Black holes "suck" only as much as the mass that they contain does.

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.

Don't Knock It! (5, Funny)

StefanJ (88986) | more than 7 years ago | (#18017342)

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.

Re:We're all going to die! (5, Funny)

General Fault (689426) | more than 7 years ago | (#18018212)

Hows the old saying go?
"With the bomb squad, you can usually stop running after the first couple of blocks. If it involves the physics department, keep going."

or perhaps

"We're pleased to announce we are still here to report the results."

Re:We're all going to die! (2, Funny)

DamnStupidElf (649844) | more than 7 years ago | (#18018824)

One of these days those crazy scientists are going to do something and we will all just disappear into a mass of energy.

Don't worry, there's always an alternate universe where the experiment fails.

Re:We're all going to die! (1)

muhadeeb (1062676) | more than 7 years ago | (#18019304)

The hadron super -collider in Switzerland is proposed to produce a blackhole albeit a scant millimeter or so in five years. Hold on to your collective you know whats.

Cue people who pretend they understand the science (5, Funny)

CRCulver (715279) | more than 7 years ago | (#18017138)

in 5, 4, 3, 2, 1...

Re:Cue people who pretend they understand the scie (3, Interesting)

Anonymous Coward | more than 7 years ago | (#18017208)

You might not believe it but there are some bona-fida scientists skulking about slashdot.

Never mind the science, give me my proton pack! (1)

spun (1352) | more than 7 years ago | (#18017310)

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 [wikipedia.org] are just around the corner.

Ahhhh, I love the smell of burning ectoplasm in the morning! It smells like victory.

Re:Never mind the science, give me my proton pack! (0)

Anonymous Coward | more than 7 years ago | (#18018010)

Duh. If you use a backpack cyclotron, it doesn't matter. 2 miles is just a matter of about 3000 loops around the circle. Then you hit the particle stream with that little plasma wakefield and bam! You get 2 GeV for the price of 1. Gozer's toast.

Re:Cue people who pretend they understand the scie (2, Funny)

Anonymous Coward | more than 7 years ago | (#18017468)

Cue the crackpots who deny the science.

Re:Cue people who pretend they understand the scie (4, Insightful)

Mr. Underbridge (666784) | more than 7 years ago | (#18019122)

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!

Re:Cue people who pretend they understand the scie (0)

Anonymous Coward | more than 7 years ago | (#18020926)

http://en.wikipedia.org/wiki/Plasma_acceleration [wikipedia.org]

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

Re:Cue people who pretend they understand the scie (0)

Anonymous Coward | more than 7 years ago | (#18019158)

wow, you're good.

Don't we all love comparisons for laymen (0)

exp(pi*sqrt(163)) (613870) | more than 7 years ago | (#18017152)

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
No it isn't.

(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.)

Re:Don't we all love comparisons for laymen (0)

Anonymous Coward | more than 7 years ago | (#18017176)

Twice the energy is about 41% more speed. Twice the speed is four times the energy. E=m (v^2) / 2

Re:Don't we all love comparisons for laymen (1)

andy314159pi (787550) | more than 7 years ago | (#18017284)

the 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 [wikipedia.org] with the Lorentz factor [wikipedia.org] in that expression are needed to get the correct relativistic energy.

Only for small values of v (5, Informative)

benhocking (724439) | more than 7 years ago | (#18017314)

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

Re:Only for small values of v (1)

arodland (127775) | more than 7 years ago | (#18017854)

Your point is right, but your math at the end there is a little flaky. What it actually works out to is: E = mc^2 = \gamma m_0 * c^2 ~~ m_0*c^2 + (1/2)m_0*v^2 and if we subtract out the rest energy we get the classic "1/2 mv^2" for v near zero.

Re:Only for small values of v (2, Insightful)

NeutronCowboy (896098) | more than 7 years ago | (#18017920)

What the.... sigh. Something that ought to be pointed out here is that E=mc^2 is generally understood to be E=m0c^2, where m0 is rest mass. Very rarely is this equation used for total energy (Kinetic + rest energy). See good ol Wikipedia for more info. Also, for v much smaller than c, 1/sqrt(1-v^2/c^2) approaches 1, as v^2/c^2 approaches 0.

Technical equation (1)

benhocking (724439) | more than 7 years ago | (#18019308)

You are right. It's been a while since I've delved into relativity (I'm embarrased to admit that my Master's thesis [virginia.edu] 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.

Also, for v much smaller than c, 1/sqrt(1-v^2/c^2) approaches 1, as v^2/c^2 approaches 0.

True. However, for v significantly smaller than c, 1/sqrt(1-v^2/c^2) approaches [wikipedia.org] 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.)

Re:Only for small values of v (1)

zippthorne (748122) | more than 7 years ago | (#18019330)

I was going to point out that you can get some of your about eq's and other mathematical symbols by using html charaacter codes. I'm nearly certain you USED to be able to sneak them in through the slashcode. Why would this feature be disabled on a forum for technically minded people?

Re:Only for small values of v (1)

benhocking (724439) | more than 7 years ago | (#18019374)

Yeah, I tried using ² and ≅ to no avail. (sigh)

I also forgot to use &lt; to say for v << c, which is why my end looks cut off.

Re:Only for small values of v (2, Funny)

larpon (974081) | more than 7 years ago | (#18020022)

bah... The average Joe read your posts like this:

E=<some weird character line up> = <some more blur>
<assorted english words>
Conclusion: WTF?!1

I'll admit I'm point blank on this.

Another particle in a box (3, Informative)

HomelessInLaJolla (1026842) | more than 7 years ago | (#18017304)

In terms of solving the relevent math covered in the study of Quantum Mechanics and Molecular Spectroscopy [google.com] (senior Inorganic Chem II [rose-hulman.edu] at my alma mater), pumping energy into an electron [slashdot.org] 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.

Re:Don't we all love comparisons for laymen (1)

drinkypoo (153816) | more than 7 years ago | (#18017400)

Well sure, it's a lot more like taking a car that accelerates from zero to whatever in however many feet, and then doubling its mass in an inch. While more accurate, studies have shown that most people have no fucking idea what mass really means, so the stupid race car simile was utilized even though it was, well, stupid.

Re:Don't we all love comparisons for laymen (0)

Anonymous Coward | more than 7 years ago | (#18019100)

Mass is caused by the Higgs syrup running over the side of your positron pancakes and getting onto your electron bacon.

Re:Don't we all love comparisons for laymen (2, Insightful)

exp(pi*sqrt(163)) (613870) | more than 7 years ago | (#18017598)

Hmmm...I am going to justify myself.

A simile depends on having a kind of mapping between one domain and another. These allow you to use reasoning from one domain to reason in another. That's why they're so useful - by using such a mapping, people inexperienced in one domain can still reason in it by leveraging their experience in another. For example, when Shakespeare says "Shall I compare thee to a summer's day" he points out that some of our reasoning about summer's days can be applied to people too. For example, just as many people are disappointed when we know there will be no more summer's days as autumn approaches, we know that Shakespeare would be disappointed if separated from the subject of his sonnet for an extended period of time. We know this even though he doesn't say it explicitly because he has set up a mapping that allows us to reason about his subject.

Sometimes the mapping is a direct translation. For example if someone says that detecting a pulsar with a new radio telescope is like seeing a candle on the moon we can guess that maybe the power being received from the pulsar is the same as the power received from a candle on the moon. Sometimes it's a scaling. For example if someone says that a flea's jump is like a human jumping over the Empire State building we guess that if we were to scale a human down to the size of a flea, then applying the same scaling to the said building would reduce it to the height of a flea's jump.

So now I can say what my complaint about this simile is. It gives no idea what the mapping is. Actually, it's worse, I can partly see what the mapping is, but the concepts I use to do this aren't in the grasp of the very people it is designed to help. But even in this case it's only a partial understanding. I don't know if the energy of the car is meant to be literally the same energy as that of the particle. I don't know if the 250ft is meant to be taken literally. And the stupid thing is that ordinary people have no intuition about the energy stored in a non-relativistic moving object, let alone a relativistic one. So most people are probably inclined to try to set up an interpretation of the mapping in terms of the car's velocity - and that's the wrong mapping.

Re:Don't we all love comparisons for laymen (1)

mysticgoat (582871) | more than 7 years ago | (#18020036)

Imagine a world where a layman who has a bad map of new territory is better off than if he had no map at all...

E=1/2 m v^2 (4, Informative)

leehwtsohg (618675) | more than 7 years ago | (#18017162)

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.

Re:E=1/2 m v^2 (4, Insightful)

qbwiz (87077) | more than 7 years ago | (#18017294)

Well, you're right when you don't account for relativity. When you're going at .99c and you double your energy, you don't start going at 1.4c.

Re:E=1/2 m v^2 (4, Funny)

UbuntuDupe (970646) | more than 7 years ago | (#18017520)

I didn't know 60 mph was close to c. Maybe for large values of 60? ;-)

Re:E=1/2 m v^2 (1)

myowntrueself (607117) | more than 7 years ago | (#18018696)

I didn't know 60 mph was close to c. Maybe for large values of 60?

Or relativistic hours? I mean 'miles per hour' for a person travelling at relativistic speeds would be different from 'miles per hour' for a non-relativistic observer wouldn't it, since time dilation would mess with the hours? Or something like that?

Re:E=1/2 m v^2 (1)

dkf (304284) | more than 7 years ago | (#18018946)

No, miles-per-hour are exactly the same for an observer moving at relativistic speeds as for a stationary observer. This is not intuitive, but it is true nonetheless. It's just that the stationary observer's miles-per-hour are not the same as the relativistic observer's, which you can regard as being the results of Lorentz contraction on the spatial dimension parallel to the direction of travel and corresponding time dilation so that things still do not look different to those on the inside.

(I think I got that right; long time since I did SR...)

Re:E=1/2 m v^2 (0)

Anonymous Coward | more than 7 years ago | (#18020234)

quite clear they are operating in base c/60.1 here :)

Re:E=1/2 m v^2 (0)

Anonymous Coward | more than 7 years ago | (#18017584)

That's not the point. The point is that the analogy is wrong. Going from 60mph to 120mph is doubling speed. If the accelerator doubles the energy of the particles, it is neither doubling speed, nor is it analogous to the car example in terms of energy.

Re:E=1/2 m v^2 (1)

kestasjk (933987) | more than 7 years ago | (#18018896)

Speed isn't the important thing in a particle accelerator. They're not racing the electrons, they're smashing particles.

Re:E=1/2 m v^2 (1)

cyberanth (952084) | more than 7 years ago | (#18017434)

In this domain though, doubling the energy corresponds to a very small increase in speed. E = p^2/2*m is just the first order term in an expansion of E = Sqrt[m^2*c^4 + p^2*c^2], and p = m*v*(1 - v^2/c^2)^(-1/2). Thus doubling the energy corresponds to a speed difference of 0.0166415572 m/s. That's 5.5e-9 % increase in speed. One way to think of if (although technically it's not correct), the mass of the electron at 42GeV is 82,000 times it's rest mass, and the velocity increase needed to increase its energy is tiny in such as high energy domain.

Re:E=1/2 m v^2 (0)

Anonymous Coward | more than 7 years ago | (#18018422)

More to the point, to double the kinetic energy of a car going 60 mph, it need only be accelerated to 85 mph. (85*85)/(60*60) is about 2. As previously stated, the car will have 4 times the kinetic energy at 120 mph as it does at 60 mph. (120*120)/(60*60) = 4.

E = 0.5 * M * V**2

KE = m*v^2 (1)

tor528 (896250) | more than 7 years ago | (#18017164)

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.

International Linear Collider (2, Informative)

erosannin (898004) | more than 7 years ago | (#18017186)

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?

Re:International Linear Collider (1, Informative)

Anonymous Coward | more than 7 years ago | (#18017410)

The International Linear Collider will supplant the Large Hadron Collider some time after 2015

The ILC will not "supplant" the LHC, they are completely different machines, accelerating different kinds of particles, making the suitable for different kinds of studies.

Re:International Linear Collider (1)

bockelboy (824282) | more than 7 years ago | (#18017542)

Yes, it'd be great if we could accelerate particles like this for the "next next big thing" after the ILC. Unfortunately, the energy levels using these and other exotic techniques are not yet all that high.

Notice that the electrons are spun at SLAC for about 2 miles up to 43 GeV, then this technique about doubles the energy to 85 GeV in 33 inches.

However, they still need to show that this can be done again and again; the ILC will be in the range of 500-1000 GeV. I only work with particle physicists (mathematician at heart), but I understand going from 85 -> 1000 GeV using this tech might be revolutionary, rather than the evolutionary

Planning a large-scale evolutionary experiment is much easier than planning a large-scale revolutionary experiment. Like most things, they need to show this scales a couple factors more before they can build a multi-billion dollar accelerator. The ILC and LHC are, after all, very clever evolutions of previous successful smaller experiments.

Still, the great thing about science is surprises do happen. I think it's unlikely that the "next next" accelator will be plasma based but Damn - that'd be cool.

Luminosity (4, Informative)

jpflip (670957) | more than 7 years ago | (#18017836)

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.

Re:Luminosity (1)

myowntrueself (607117) | more than 7 years ago | (#18018718)

You can't just accelerate a few particles to high energies and say you are done. You're looking for rare processes

Unless you are just looking to punch great smoking holes in tanks or something?

Re:International Linear Collider (0)

Anonymous Coward | more than 7 years ago | (#18020396)

All of these systems go undergo upgrades over time. Heck, the LHC itself is essentially a (very big and expensive) upgrade of the previous LEP collider at CERN. Should these plasma accelerator technologies mature, they can probably be retrofitted as booster stages to the upcoming generation of particle accelerators. And just think how impressive that will be. :-) For the initial acceleration stages, plasma doesn't really replace existing technology.

Of course, as impressive as this all is for science, you just know some DARPA or Air Force guy is getting a hard-on thinking about ways to turn these into battlefield weapons. Vastly increasing energy in compact packages for short pulses sound like exactly the sort of thing military applications would find useful.

innerspace (5, Funny)

President_Camacho (1063384) | more than 7 years ago | (#18017218)

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.

Re:innerspace (4, Funny)

Dachannien (617929) | more than 7 years ago | (#18017302)

using electrons for their race cars and plasma for the afterburners

And their wives still say they're compensating.

Re:innerspace (2, Funny)

boarsai (698361) | more than 7 years ago | (#18019060)

And their wives still say they're compensating.

So what you're really saying is we should have done physics instead of IT, as they have the women. Bastards.

Re:innerspace (1)

edwardpickman (965122) | more than 7 years ago | (#18017516)

Those sound like really small physicists

At least we know what happened to the Indonesian Hobbits. They didn't die out the evloved into physicists.

Re:innerspace (0)

Anonymous Coward | more than 7 years ago | (#18018884)

You should see the paintbrushes they needed to use to paint the flames on the sides!

Good way to die of acceleration (1)

Marxist Hacker 42 (638312) | more than 7 years ago | (#18017222)

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.

Re:Good way to die of acceleration (0)

Anonymous Coward | more than 7 years ago | (#18017256)

Say hellow to jello bones

okay. hello, jello bones.

are you any relation to cartilage head?

Re:Good way to die of acceleration (0)

Anonymous Coward | more than 7 years ago | (#18017890)

That's cause you forget to bring the inertial dampeners online first.

Bah! (1, Offtopic)

jcr (53032) | more than 7 years ago | (#18017358)

In my day, we just banged rocks together! And we were grateful!

-jcr

Re:Bah! (1)

skoaldipper (752281) | more than 7 years ago | (#18017664)

Bah! In my day, and in my state, we just bore through rocks! And we WERE grateful!

Unfortunately, the SSC 54 mile ring would have accelerated protons to 20 TeV and was never completed. I can only imagine with this plasma infusion what might have been and never was. If only...

Re:Bah! (0)

Anonymous Coward | more than 7 years ago | (#18018114)

That's nothing! Back in my day, we had to accelerate the particles by hand!

how energy changes as v -- c (2, Informative)

andy314159pi (787550) | more than 7 years ago | (#18017384)

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 [wikipedia.org] with the Lorentz factor [wikipedia.org] 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.

For the Americans here (4, Funny)

lelitsch (31136) | more than 7 years ago | (#18017386)

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)

Obligatory Response (1)

drinkypoo (153816) | more than 7 years ago | (#18017500)

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.

Re:Obligatory Response (4, Funny)

It'sYerMam (762418) | more than 7 years ago | (#18017622)

Besides, only engineers use decimal measurements, everyone else uses fractions.

Unless you're irrational, that is.

Re:Obligatory Response (2, Funny)

IthnkImParanoid (410494) | more than 7 years ago | (#18018234)

This division in our ranks is merely imaginary; don't let it keep us from finding the root of the problem.

Winged electrons (0)

Anonymous Coward | more than 7 years ago | (#18017406)

Now they are capable of doubling the energy of electrons.

Does it involve teeny-tiny little cans of Red Bull?

The example is stupid... (3, Insightful)

sealawyer2003 (688442) | more than 7 years ago | (#18017626)

'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.

So let's try this: (1)

Ungrounded Lightning (62228) | more than 7 years ago | (#18017998)

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-) )

I actually work on this at USC!!! (5, Informative)

Brietech (668850) | more than 7 years ago | (#18017692)

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:
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 . . .or at least something close to that!

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.

Re:I actually work on this at USC!!! (1)

Lawrence_Bird (67278) | more than 7 years ago | (#18017888)

I've not read any of the technical papers on this yet but off hand I wonder if a) you can ever get the same luminosity as more traditional methods and b) how well can this be used for heavier particles?   I suppose the first real world use
would be as an injector?

Re:I actually work on this at USC!!! (4, Informative)

Brietech (668850) | more than 7 years ago | (#18017976)

As far as I understand it, it doesn't work nearly as well for heavier particles (I assume you are thinking protons?). Especially ones with a positive charge. The heavy mass of the protons compared to the electrons in the plasma cloud are what allows the "wakefield" to be created in the first place. When we model this stuff, the ions move so slowly compared to the electrons that we generally just assume that they are static for the duration of the beam passing through the oven (pico-femto second range). As I mentioned earlier, this will most likely always show up as an "afterburner" that goes at the end of a traditional linac.

Re:I actually work on this at USC!!! (1)

sanman2 (928866) | more than 7 years ago | (#18019118)

Can you maybe use this thing for accelerating other exotic particles, like muons? I'd read that muon colliders are being researched because they as point particles might arrange for cleaner point-collisions with enough kinetic energy to serve as "Higgs factories". A "Higgs factory" device which could produce lots of Higgs particles might then make it much easier to find/study the "God particle". (Even exploit it?)

Because laser wakefield / plasma wakefield accelerates things so quickly and so suddenly, perhaps it would enable muons to be accelerated and collided sooner, before they have a chance to decay. And the small size of these wakefield accelerators might make them more economical and feasible.

What do you think?

Re:I actually work on this at USC!!! (1)

Pollardito (781263) | more than 7 years ago | (#18018070)

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.
sounds like a slingshot pass in NASCAR. Shake-n-Bake, baby

Wow (0)

Anonymous Coward | more than 7 years ago | (#18018108)

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?

Re:I actually work on this at USC!!! (1)

Bananenrepublik (49759) | more than 7 years ago | (#18018762)

Understandably, one wants the bunches to be small. Wouldn't this mechanism tear the bunches apart, and give them much higher temperature (i.e. spread out energy distribution)?

Re:I actually work on this at USC!!! (4, Informative)

Galahad2 (517736) | more than 7 years ago | (#18019518)

I attended a talk from one of the primary investigators on this project a few months back. The system does indeed spread out the distribution, which can be bad for some circumstances. When all you care about is the peak energy, however, it's great. They call it a plasma afterburner.

One thing that isn't obvious is that you can't use two of these devices to double the energy twice. One doubling is all you got. Apparently there's some theorem in plasma physics that a Gaussian distributed pulse (as SLAC is) can only be energy-doubled by any method or methods once. I don't know the details of this, and I might be misrepresenting it, but there you go.

By the way, I think you have a misconception about temperature. It's true that a higher temperature gas has a wider energy spectrum, but the primary piece of information you're interested in is the average velocity. The statistical distribution is a function of only one variable -- you can't "spread out" the distribution to increase the temperature without simply dumping energy into the system. If you somehow separated the particles into low average energy and high average energy, you'd just have two classes of particles with two temperatures, not one cumulatively higher one.

Re:I actually work on this at USC!!! (1)

ridgecritter (934252) | more than 7 years ago | (#18019248)

Is it likely that these accelerators can be cascaded to get higher energies?

Re:I actually work on this at USC!!! (0)

Anonymous Coward | more than 7 years ago | (#18019860)

They seem to think so. I hear Dr. Freeman has been assigned to follow up on the idea.

Re:I actually work on this at USC!!! (0)

Anonymous Coward | more than 7 years ago | (#18019288)

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.

I know. I heard you trying to use this line at the bar last Friday.

Re:I actually work on this at USC!!! (1)

DigiShaman (671371) | more than 7 years ago | (#18019850)

Excuse my ignorance, but I don't have the slightest clue as to why this is important.

Based on my limited understanding of what you said, its application could be used for some "Energy Weapon". Yes? If so, just imagine how much the military would pay USC for it. At that point, I guaranty you wouldn't need another grant for a long long time ;)

Re:I actually work on this at USC!!! (1)

diablomonic (754193) | more than 7 years ago | (#18021058)

my laymans understanding is: particle accelerators are used to study the basic building blocks of our universe, and as they get more powerful (ie they can give the accelerated particles higher energies ) they see new levels of building blocks EG:

imagine the world is made of Lego shaped into the form of duplo. Before we had particle accelerators, we might have thought we were made of duplo. By smashing the "faux duplo" together, we realize there's Lego in there(*). if we throw it even harder at each other, the Lego might break and we would realize we were made of plastic, or it might stick together and we would realise we can make our own "custom faux duplo". if you threw the Lego hard enough it might break into plastic molecules, then atoms, then protons neutrons and electrons, then.... etc etc. each time this happens, we learn about a new possible building material or exploitable phenomena.

(*) and we all know lego is much more useful than duplo for building cool stuff :)

This invention basically doubles the output power of any(*) other lego throwing device we make (*)for a limited range of any's :)

Err, 120mph? (1)

DreamCoder (679179) | more than 7 years ago | (#18018178)

"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.... Because electrons already travel at near light's speed in an accelerator, the physicists actually doubled the energy of the electrons, not their speed."

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...

Re:Err, 120mph? (1)

1u3hr (530656) | more than 7 years ago | (#18019574)

Imagine a car...

You KNOW when someone use a car analogy to "explain" a highly technical or abstract concept that it will make no sense. And worse, will start up a whole bunch of threads about cars, driving, etc, etc.

So? (1)

SpaceballsTheUserNam (941138) | more than 7 years ago | (#18018658)

does anyone ACTUALLY care about this? slownewsday

Re:So? (1)

Galahad2 (517736) | more than 7 years ago | (#18019766)

Actually, it's a really, really big deal for experimental particle physics. Accelerator size is directly proportional to maximum energy for conventional acceleration. For a given energy, this thing halves the required size of the building (not to mention the cost). That's a big deal when you're talking about 100 km accelerators costing tens of billions of dollars. In fact, if SLAC were a little big bigger, they could reach the energies of CERN and scoop them on the Higgs boson.

WHEW (0)

Anonymous Coward | more than 7 years ago | (#18020176)

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.

Slashdotism (1)

davidwr (791652) | more than 7 years ago | (#18021064)

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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