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Comments: 167 +-   Fastest Waves Ever Photographed on Tuesday October 31 2006, @10:16PM

Posted by kdawson on Tuesday October 31 2006, @10:16PM
from the wakefield-at-.9997-C dept.
science
starfoot writes, "Pictures of the fastest waves ever photographed, traveling at 99.997% of the speed of light, were presented today at the APS Division of Plasma Physics meeting in Philadelphia. The waves were formed in the wake of an intense laser pulse passing through a plasma of electrons and ionized atoms. The waves create enormous electric fields (over 100 billion electron volts/meter), which can be used to rapidly accelerate charged particles to high energies in the span of a few meters. The pictures will help scientists better understand wakefield interactions — an important factor in their quest to replace machines that accelerate particles over the course of miles with compact, tabletop versions. High energy particle accelerators are vital for cutting edge physics and many types of medical therapy, and miniaturizing them would be a boon for both basic physics research and medicine."
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  • Yeah right (Score:4, Funny)

    by UbuntuDupe (970646) on Tuesday October 31 2006, @10:19PM (#16668545) Journal
    I bet it was just photoshopped. Gimme ten minutes, and I can give you a wave doing 99.999% of the speed of light.
      • IANA particle physicist, but I believe the "photograph" in question is in fact the grayscale interference pattern on the plane beneath the 3D (spectro?)graph.

  • Whoa (Score:3, Funny)

    by 0racle (667029) on Tuesday October 31 2006, @10:25PM (#16668607)
    Thats hot.

    • Medical Applications? (Score:4, Interesting)

      by dch24 (904899) on Tuesday October 31 2006, @11:49PM (#16669241) Journal
      many types of medical therapy

      Hey, so I understand the applications in Physics of desktop particle accelerators, but what kinds of medical therapy use particle accelerators? Wikipedia suggests creating rare "proton-heavy" isotopes [wikipedia.org], but I'm having trouble finding more about what kinds of "killer apps" (pun intended) would be enabled if there were cheap desktop particle accelerators. Someone in med school?
      • Cyclotrons and nuclear reactors are used for creating radioactive compounds for PET (Positron Emission Tomography) scanners, other types of radiography and radiation therapy. PET scanners in particular are often built with an adjoining cyclotron facility to produce the usually fairly short lived radioactive compounds.

        Synchrotron radiation also looks like it's useful for a variety of both imaging and radiation therapy techniques. Rather than hauling patients off to the synchrotron facility you could take t

  • Ok, seriously... (Score:4, Interesting)

    by Lord Aurora (969557) on Tuesday October 31 2006, @10:37PM (#16668713)
    Wouldn't the fastest waves ever photographed be...you know...light waves? And don't we photograph those every day? Correct me if I'm wrong, but light goes 100% the speed of light.


    Dead serious, I know there's a difference here between my family photo album and the pretty graph thing FTFA, could someone explain to me why photographing LIGHT doesn't count here?

    • When you photograph light, you can't see the wave. Taking the classical E&M view for a second, a light wave is an oscillation between the magnetic and electric fields - you can't photograph that. TFA is admittedly sketchy with the details, but these seem to be waves in the "globs of stuff moving around" sense, like water or sound waves.

    • There's currently no way to take a snapshot of a single photon in motion and produce an image out of it. An ordinary photograph captures the effect of many millions of them impacting a chemical, so that's not really the same :)
    • I don't think you can directly photograph a single photon, what you'd need is a medium with process that senses the photon passing by, and changes state accordingly, something similar to how the bubble chamber photographs charged particles - you don't actually capture the particle, but you look at the myriad of photons emitted by the bubbles formed in the superheated liquid. The story above too photographs a medium - plasma - and it's state. That's how you get to see single particles.
    • These are matter waves. The summary should really say fastest matter waves ever. You're right... the same though occurred to me.

  • Fast, but how fast? (Score:4, Funny)

    by abscissa (136568) on Tuesday October 31 2006, @10:44PM (#16668777)
    If you made instant coffee in the microwave, would you go back in time?
    • Only if you made instant coffee while you're in the microwave...
    • Yes, but the field is localized entirely within your microwave.. that's why instant coffee in a microwave tastes even worse than regular instant coffee, it's actually thousands of years old.
  • Hubble telescope pictures consist of photographing waves travelling at 100% of the speed of light in vacuum by definition!

    For the pedants technically your own photographs generally don't count because the refractive index of air (1.0008) actually means that light waves in air will only travel at 99.92% of the speed of light in vacuum.
    • Hubble telescope pictures consist of photographing waves travelling at 100% of the speed of light in vacuum by definition!

      Wrong - the Hubbel uses waves travelling at c to record the electro magnetic emissions of distant bodies in our universe, it does not photograph the waves themselves. To match what was done in TFA, you'd have to photograph, er, photons. Not the same thing at all.

      Again - you'd have to photograph photons themselves to match the experiment, regardless of the RI of the medium they're travell
  • Wow man......surf's up, man. Fast waves? I'm in! Time to hit the beach!

  • How easy is it? (Score:3, Interesting)

    by Gracenotes (1001843) <wikigracenotes@gma i l . com> on Tuesday October 31 2006, @10:53PM (#16668859)
    100 billion electron volts/meter sounds like a lot. In reality, if the same amount of physical energy were applied to a paper clip over one second, it would be moved 8.0108823 microns. That's 0.000315389067 inches; 0.00080108823 centimeters. Completely not impressive.

    The reason this is so awesome is that scientists can apply this to nanotechnology -- actually, the prefix "nano" is not small enough. After all, everything moves in waves, but these waves are only noticeable on a small enough scale. On this scale, electric energy is so much more important than gravity. The fact that this energy is electric and not physical means that, instead of bumping atoms around continuous for a month, something might happen sooner. The fact that it's been proven done might help with something, like (for example) supplying a power source. The question is, "How easy is it to synthesize this phenomenon, and is it worth it?"

    What excites me most is the fact that
    a technology that could make tabletop high-energy particle accelerators a reality.
    Are we still afraid of put explosives into our chemistry kits for fear that kids might get hurt? Just like how, around Sputnik time, the US gov't tried to make all of the children in its public education system little scientists of future, it is (seriously) important to get kids interested in science, math, and academic pursuit at a young age. Can a little kid read the KJ version of the Bible at 4 years old, as was done in days of yore?

    It would be a good thing that, with this increased technology, scientists would try to give nuclear chemistry to the public and make atomic physics more tangible. There was an ambitious project some time ago that wanted to create a huge electromagnetic field somewhere in Texas. It was shut down because the US gov't saw no use of it. If this technology can do something as simple as power a light bulb, the public will notice. No one cares if Element 118 is created in a matter of seconds instead of across the span of a week, but if people can actually see something, this is better for science in general. (So long as John Galt doesn't get angry.)

    • Re: (Score:3, Informative)

      by agentcdog (885108)
      How about: not even wrong. eV/m is a FIELD STRENGTH. eV = energy. 1eV is a small amount of energy, but you cannot apply any amounts of eV/m to any object. Remember phys 101? Dimensional analysis?
      Haw did he get modded up? Modders: If you don't know what he's talking about, don't mod him insightful. I feel like that duck in the barber shop.
      Note: You could imagine what would happen if you put a paperclip in this field, but without a net charge it aint movin'. If there were a net charge you better get o

    • Re: (Score:3, Informative)

      by Phanatic1a (413374)
      100 billion electron volts/meter sounds like a lot. In reality, if the same amount of physical energy

      *Bzzzt*. Wrong with the second sentence.

      100 GeV/m isn't an amount of physical energy. It's a field strength.

      It's still not a lot on a macroscopic scale (about 1.6E-8 joules per meter). But, jeeze, at least get your units right before you start doing dimensional analysis.

  • exclusive pics (Score:3, Insightful)

    by Timesprout (579035) on Tuesday October 31 2006, @11:41PM (#16669181)
    o/
    /|
    / \

    This is me waving so fast my arm looks stationary
  • I'm a bit of a laymen, the huge stadium sized accelerator uses some kind of giant magnetic field to propel a particle and split atoms at the other end right?

    Why do we do this again? Just to detect the junk that's emitted from the destroyed atom? Why do hospitals need a tabletop accelerator?

    Thanks for filling me in :)
  • I measured these but I can't make up my mind if they're a particle or a wave.

  • Speed Limit (Score:3, Funny)

    by bmo (77928) on Wednesday November 01 2006, @02:15AM (#16669977)
    +-----------+
    | _ 5MPH__ |
    | No Wake_|
    +----+-----+
            |
            |
    ~~~~~~~~~~~~

    The harbor master isn't going to like this one.

    --
    BMO
  • A few thousand of these running in parallel may offer methods for creating meaningful amounts of antimatter.
  • ...are of waves traveling *at* the speed of light.

    You kids and your new-fangled sub-light speed waves.
    Get offa my lawn!

  • ``Pictures of the fastest waves ever photographed, traveling at 99.997% of the speed of light ...''

    Rafting is recommended to experienced rafters only.
  • What might I want to do with a tabletop particle accelerator?

  • Give me one of those (Score:3, Insightful)

    by PalmKiller (174161) on Wednesday November 01 2006, @12:24PM (#16675039) Homepage
    I want me one of those tabletop accelerators for my shop, oh and a tabletop nuclear fusion reactor would be nice too.

    • Re:Request for Clarification (Score:4, Interesting)

      by wass (72082) on Tuesday October 31 2006, @10:39PM (#16668733)
      Particle physics has nothing to do with it, it's just straight old electrodynamics (E&M). Your assumption is correct, they specically say it's the electric field, and the slashdot blurb incorrectly inserts the word 'electron' there.


      The electric field is merely the negative gradient of the scalar potential (ie, voltage)*. So in SI it will have units of Volts/Meter.


      * (Just in case any E&M sticklers want to point that my electric field definition here ignores the contribution from vector potential, just assume a time-independent gauge).

      • Particle physics has nothing to do with it, it's just straight old electrodynamics (E&M). Your assumption is correct, they specically say it's the electric field, and the slashdot blurb incorrectly inserts the word 'electron' there.

        The electric field is merely the negative gradient of the scalar potential (ie, voltage)*. So in SI it will have units of Volts/Meter.

        Since the electric field is interacting with electrons, it is actually reasonable to use units of electron volts per meter. The quantity desc

        • Nope. Electron-volt is a measure of energy.

          Volts have dimension of: m^2*s^-3*kg*A^-1
          Electron-volts have dimension: kg*m^2*S^-2

      • Re: (Score:2, Informative)

        by aditi (707829)
        Electron Volts per Meter (eV/m) is actually a perfectly valid measure of electric field. It's how much energy an electron going through the field would gain per meter. To get the actual electric field, you would just divide by the elementary charge e = 1.6*10^-19 C. In relativity and particle physics, one often sees masses expressed in eV/c^2 and momenta in eV/c. It's just a convenient notation to absorb unweildy constants such as e and c, and show the numbers that really matter.
    • You're right - an eV is a unit of energy. It's the charge of an electron multiplied by a volt - in other words, it's the energy gained by an electron accelerated through a one volt potential.

      However, somewhat confusingly, it's also often used as a unit of mass - technically the units are eV/c^2, but in the particle physics grand tradition of insanely terse notation, the c^2 is usually dropped and eV is used as a unit of mass.

      • Re: (Score:3, Insightful)

        by kravlor (597242)
        And in the realm of plasma physics, the eV is a common surrogate for temperature, in which Boltzmann's constant k is omitted. It's always fun when you have multiple definitions for the same abbreviation in exciting, but overlapping, branches of physics! Since I was at this talk early this morning, it certainly was exciting to see the progress in this field.
    • "I don't see the added benefit of studying such interactions and building particle accelerators which cost a bomb, or miniaturizing them, which would cost even bigger a bomb."

      A "usability engineer" can't see the point and has the costing wrong, what a surprise!
    • Yes, what possible benefits could there be to machines that help probe the basic nature of matter?

      The CRT didn't have much relevance to everyday life in 1897 either, nor did that first bigass transistor from Bell Labs. If it weren't for money that was spent on pie-in-the-sky / "basic" research, there'd be nothing to do applied research on.
    • Given that that was a pulse laser, this might be possible. Depends on how much energy needs to be dissipated. Frankly, I think the radiation shielding requirements would be more troublesome than the laser power. I imagine a few meters of concrete laced with ball bearings is necessary to play with this safely (assuming energy levels that would generate useful physics). Not something that you stick on your desktop.

      • Re: (Score:3, Interesting)

        by Oink (33510)
        These laser pulses are on order 100 femtoseconds. That's 100 * 10^-15 seconds. That works out to only about 3 Watts assuming the 30 TW and 1 shot per second (which is reasonable).

        This is nothing compared to the petawatt laser that is being built in the same building here at UT in the same building that this published research was done (one door down from my office in fact). They can only take a shot every 45 minutes after charging a huge bank of capacitors.
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