Tim writes:
Reading a BBC article yesterday about the resurrection of cold fusion, I ran into a mention of the National Ignition Facility – which, I discovered, is the most powerful laser system on earth. 12,700 tons of rebar! 500 trillion watts of photonic destruction. But best of all, an absolutely superior website, at least by the standards of most federal internet presence. The layman’s overviews are clear without being dumbed-down, and the in-depth stuff has enough sciency fodder to keep we nerds fat and happy for hours. My point is: kudos to them. And lucky us.BTW, the NIF has begun its firing tests, and is expected to reach full operability this year. Awsoma power!
We’re going to need a bigger Jiffy-Pop.
Friedman wrote about this in an interesting column a few days ago. It sounds very cool.
He says a lot of scientists are still skeptical about this specific process being scaled up, but that research like this is the key to true energy independence.
Seems to be a dead link.
I cannot wait to witness the firepower of this fully armed and operational science station!
Erm… The link’s a bit dead.
You may fire when ready, captain.
The link is https://lasers.llnl.gov/programs/nif/about.php
I was under the impression that the University of Texas operates the most powerful laser on the earth, topping out at 1 petawatt.
http://blog.wired.com/wiredscience/2008/04/texans-build-wo.html
Regarding the NIF vs. the University of Texas laser, it depends on what you mean by “powerful.”
The UT laser facility has the NIF beat on peak power, but the NIF is going wallop it in total energy.
It’s like this, power has a very specific physical meaning– energy/time. These lasers are pulsed lasers, they fire off discrete pulses of light with some repetition rate rather than the continuous emission of light that you get from something like a laser pointer. So when we talk about the power of a pulsed laser we can refer to either the average power which is the total energy delivered per second (in watts where 1 watt = 1 joule/second), or we can refer to peak power which is the total energy delivered in one pulse.
The average power takes into account the entire duty cycle and includes all pulses in one second as well as all the time when the laser is “off” so it is invariably lower than the peak power.
To illustrate the difference, I’ll talk about my lasers first. I like lasers, I have a laser pointer that is bright green and I work in a research lab with a laser that is usually red or invisible (IR). My 5 mW laser pointer delivers 5 mJ of energy in 1 second, continuously. On a good day the laser in our lab puts out 750 mW average power. But our laser is a pulsed laser with a repetition rate of around 75 MHz. To figure out the peak power, we first divide the average power by this duty cycle to get the energy per pulse:
(750 mW)/(75 MHz) = 1 x 10^-8 J = 10 nJ
Each pulse has around 10 nanojoules of energy, not much. If I know what my pulse duration is then I can figure out what the peak power is.
Again, on an average day (and to keep the numbers round) our pulse duration is around 100 femtoseconds, that is 100 x 10^-15 seconds. This is a very short time, very short. Light travels about 1/1000th of an inch in 100 femtoseconds (fs). Very short. Anyway my peak power is the amount of energy in one pulse (10 nJ) divided by the length of the pulse (100 fs):
(10 nJ)/(100 fs) = (1 x 10^-8 J)/(1 x 10^-13 s)
= 100,000 J/s = 1 kW
So my fairly hum-drum laser has a peak power of around 1 kW!
We got to this not by having much energy, just 10 nJ, but by having a very short pulse.
This is how the University of Texas group generates over 1 petawatt of power. They don’t generate this continuously, that would take about 100 times the average power produced by the entire world in 2004. Instead they compress in time a relatively high energy (compared to mine at least) laser pulse. Their website (http://www.ph.utexas.edu/~utlasers/ ) says that they got 1.1 PW from 186 J in a 167 fs pulse. That’s pretty spectacular.
The National Ignition facility is a whole different beast. They are using much longer pulses in comparison, 20 nanoseconds as best as I can tell. The test fire earlier this month yielded an 80 kJ pulse though. So compared to UT they are delivering over 400 times the energy, but in a space of time that is 200,000 times longer. As a result, the NIF peak power is only 400 gigawatts or so right now. They hope to achieve a full power of around 0.5 PW with 1.8 MEGAjoule (emphasis mine) pulses. That is a holy crap-ton of photonic mayhem.
So which is the more powerful? UT has the peak power for sure, but NIF rules total energy. Of course one must take into account that the NIF uses 192 beams to generate that energy. This analysis leads to only one conclusion:
LAZRZ ARE TEH ROXOR, W00T!!111!1
Okay, I either need to get back to work or go to sleep.
But is the deflectors shield operational?
Fine, fine, but who’s working on the tractor beam?
Screw that, can this thing remove my intrinsic field? I want to flash my willy at people.
You don’t need your intrinsic field removed to wave your willy about, Kaiza, but it would make it easier to disintegrate the guys trying to haul you into custody.
Forget Jiffy Pop.
Try this: http://pgrayb.googlepages.com/nif_toast
Alls you’d need is a target tracking system and a big spinning mirror and you could vaporize a human target from space!
You would prefer another target? A military target? Then name the system!
um. why does the goal of igniting a fusion reaction sound somewhat… unsafe? I mean people are worried about the LHC and all, but come on, where’s the panic about this?
I want my north american crazies to come out of the woodwork!
@OohShiny:
The problem with that is that a lot (probably most) of the North American crazies are also crazy about their guns. And this is a giant gun. That shoots lasers. pew pew pew!
Granted, it’s all very confined, and focused on a small target, but it shoots stuff so hard it creates fusion! Or it’s supposed to anyway. I think this is one “potentially world destroying project” that the north american crazies can get behind.
Disclaimer: I am a PhD student researching magnetic confinement fusion.
The NIF people keep banging on about inertial confinement fusion (ICF) being used to research future energy production, but there’s a few things they’re not telling you. Firstly, those massive lasers can fire two or three times a week, tops, otherwise all the optics tend to melt. In order to get more energy out of those tiny pellets than is used in firing the lasers, they’re going to need to burn around ten every second. Not to mention each pellet costs about $10,000. And the enormous difficulty in actually making it work. Or how on earth they plan to get the energy out.
Secondly, you should be much more worried about NIF than the LHC! The one thing that ICF experiments are really good for is nuclear weapon research. So, while there is a 1 in 10^100 chance that the LHC will destroy the world, the NIF crew are actively seeking ways of doing it!
Now, magnetic confinement fusion, on the other hand, is perfectly safe, and simply cannot be used for weapon research. Iter (http://en.wikipedia.org/wiki/ITER) will demonstrate that nuclear fusion is a viable energy source, and should be up and running sometime during 2016, and is arguably even more important than the LHC.
@scuba sm — the “pew pew pew” was priceless, thank you.
@yossarian — magnetic confinement fusion? why does that sound a) like a miniature star floating in a magnetic field, and b) so much more in line with what I imagined nuclear power generation to be about? You know, the visions of the future I had until I learned that fission power plants are really just big radioactive kettles.
“Harnessing the power of the atom” my ass. Fission’s just a messier way to make water bubble.
And speaking of bubbly water, how’s cold fusion coming along these days? still impossible?
http://www.youtube.com/watch?v=M39QJLnzcGM
http://www.youtube.com/watch?v=S2rtmoSuoL4
http://www.youtube.com/watch?v=Bh7bYNAHXxw
http://www.youtube.com/watch?v=h_Fc9ubaGAE&feature=related
http://www.youtube.com/watch?v=7wyp909mQPM
http://www.youtube.com/watch?v=OxuV3NBwrYY&feature=related
/meme exhausted!