Tuesday, October 31, 2006

Fastest Waves Ever Photographed


Pictures of the fastest moving waves ever photographed were presented this morning at APS Division of Plasma Physics meeting in Philadelphia. These shots are more than your typical pretty pictures – they represent a major advance in wakefield accelerator technology, a technology that could make tabletop high-energy particle accelerators a reality.

The matter waves, which are oscillations moving through a plasma, are known as wakefields because they are created in the wake of an ultra-intense laser pulse. The waves travel at 99.997% of the speed of light and generate electric fields exceeding 100 billion electron volts/meter.

The ability to create huge electric fields makes wakefields a promising method for shrinking the size of accelerators from miles long (like those at the Stanford Linear Accelerator Center, FermiLab and CERN) to tabletop. Small accelerators would allow universities and hospitals to take advantage of the research and medical applications afforded by an accelerator without competing for time at a major particle accelerator facility.

Much work remains before tabletop accelerators can be a reality – particularly in understanding the interactions between a wakefield, the accelerated electrons, and the laser pulse. The ability to photograph wakefields is exciting news for scientists because it allows them to explore these interactions and compare theoretical predictions to real data.

Researchers from the University of Texas designed a holographic-strobe camera to take these pictures. Their method, called Frequency Domain Holography, sends two additional laser pulses though the plasma along with the ultra-intense pulse. The additional pulses detect the oscillations and then travel through a spectrometer where they interfere and are analyzed.

An abstract of the talk and a lay language paper describing the research are available online.

30 comments:

  1. We ALL have 30TW of juice at home...

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  2. That would be Jiggly Watts, to be precise.

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  3. 30 TW? No problem, lets all get Mr Fusion

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  4. Actually, 30 TW is not a problem. These laser pulses last on order of 100 femtoseconds. That's 100 * 10^-15 seconds. You can get this kind of power by compressing your laser pulse. So what you end up with is only about 3 Joules of energy, or.. assuming 1 shot per second you're only using 3 Watts.

    P.S. I happen to be down the hall from this research group. =)

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  5. When you describe it that way, I guess it really does make sense. After all, some of the most impressive things in life happen really fast... but don't expect that explanation to work with a woman...

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  6. I just want a proton pack.

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  7. I once took a picture that included light that traveled at 100% the speed of light.

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  8. I think you mean "1.21 Gigawatts". There is no such thing as a Jigawatt (even though that is how Dr. Emmit Brown pronounced it).

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  9. Actually, im pretty sure he was making a Spaceballs reference.

    And you call yourself a nerd.

    Well, im not sure if you do, actually.

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  10. I@m quite sure it was a Back to the Future reference

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  11. There are millions of photographs of waves traveling at 100% the speed of light, so this title is miss leading

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  12. Electron volts / Meter is nonsense. The strength of an electrical field is expressed as volts / meter. Electron volts is a unit of energy, i.e. the kinetic energy an electron gains when accelerated by a potential of 1V (assuming non-relativistic speeds).

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  13. Electron volts / meter is not nonsense. 1 eV/m is the force an electric field with the strength of 1 V/m exerts on an electron placed in it (1,6 * 10^-19 N).

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  14. actually, light slows down when not in a vacuum see:
    http://en.wikipedia.org/wiki/Speed_of_light

    so most of those photos WON'T be at 100% speed of light :P

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  15. These are matter waves. I bet you've not taken pictures of stuff with mass moving that fast before.

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  16. You're right, we shouldn't have said eV/meter, the measure of the field strength is just volts/meter.

    Good catch.

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  17. Has John Titor seen this?

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  18. Accelerator physicists often talk in eV/m (or GeV/m) because the figure they're interested in is the energy gain of the particles they are accelerating per unit length (i.e. GeV/m). The electric field (V/m) is less useful. For protons and electrons they have the same value, but for heavy ions (heavier than a proton), they will be different by a factor equal to the charge of the ion. Not nonsense, just different sense.

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  19. "Has John Titor seen this"

    No, but John Tesh has.. and quite simply he said it was amazing.

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  20. Ya know, all the comments on the pictures at the speed of light are all correct! The light is traveleing at 100% the speed of light, it has to it is light. The fact that it is not in a vacumme just changes that speed. |-)

    (Just a play on the words)

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  21. even if light slows down, when not in a vacuum, wouldnt it still be the speed of light? after all light is going that fast.

    something akin to the speed of sound being slower when closer to sea level, as the air is denser.

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  22. lazergunz pewpewpew

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  23. We've gone to plad!

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  24. it's a ghostbuster's reference

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  25. Can this be used as a weapon?

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  26. How do you take a photo of a light wave? A photo uses light (or liberally some other wave to interfere) and this is then converted into an image. Light does not interfere with itself except for a tiny QED correction. Are you referring to some standing wave interferring with a medium of particle beam?

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  27. They have not taken a picture of a lightwave, but recorded a picture of a wave of "stuff" having mass - as does the roadkill in your hamburger - that traverls so fast.

    Now, you think that roadkill wouldn not have become roadkill, if it had managed to attain such acceleration before impacting upon a 16 wheeler... but you are wrong. The impact of said 16 wheeler is a stroll in the park when compared to the rapid accelerarion aforementioned roadkill-candidate would have been subjected to in this experiment. So its awesome...

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  28. It is awesome. While light is always traveling at 100% of the speed of light, it is a feat of wonder to get matter anywhere close.

    "Jigawats" is a Back to the Future reference. When the professor was explaining the energy required to operate the flux capacitor--as we all know in the scientific community--is how time travel works.

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  29. Ahh, a capacitor that holds flux - a quantity expressing the strength of a field of force in a given area.

    So it holds a quantified amount of expressions that describe force within a particular area.

    No wonder it's hard to make sense of it... damned time travel...

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