A new laser, claimed to have been fired within a laboratory in Japan, is the most powerful on Earth.
The laser is situated in Osaka University and is called the Laser for Fast Ignition Experiments or LFEX. The mighty megalaser is roughly 100 meters (300 feet) long.
The laser emits a staggering amount of energy: two petawatts or two quadrillion watts, which is equivalent to nearly 1,000 times the total of the world's electricity consumption ever. The energy of the laser beam is so vast that the laser has entered the record books as the most powerful laser ever fired, according to the researchers. The second most powerful, the Texas Petawatt Laser, emits only half the amount of power of the LFEX laser.
You may think that producing such a staggering amount of energy would require an earth-shattering amount of power. It turns out that the energy required is closer to that needed to run a microwave for two seconds, according to a statement released from the university. The only difference is that this energy, instead of being spread out over two seconds, is condensed to a time of one picosecond (a trillionth of a second). The incredible final energy of the laser beam requires the assistance of four amplifiers: glass lamps that resemble fluorescent tubes.
The researchers have been running experiments continuously for the last month to confirm the power of the laser. Currently, there are only reports from the researchers that the laser has been fired and the results are unpublished, so we'll have to sit tight for footage.
Now that the team has achieved firing the world's most powerful laser, they are going to set the bar even higher.
"With heated competition in the world to improve the performance of lasers, our goal now is to increase our output to 10 petawatts," said Jyunji Kawanaka, from Osaka University.
Borgholio wrote:I think a 10 petawatt laser could carve up an asteroid pretty nicely if it could hold the beam for more than a fraction of a second...
No need to hold the beam if they can pulse it quickly enough.
The same amount of energy is still required to destroy an asteroid. A watt is energy/time, and energy can be applied arbitrarily quickly. Had they kept the laser on for a second, they would have delivered 2 petajoules of energy which can take out a medium sized asteroid. But they didnt. They kept the laser on for a miniscule fraction of a second.
If they pulse the laser fast enough, the total energy required to actually power it goes up.
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Alyrium Denryle wrote:The same amount of energy is still required to destroy an asteroid. A watt is energy/time, and energy can be applied arbitrarily quickly. Had they kept the laser on for a second, they would have delivered 2 petajoules of energy which can take out a medium sized asteroid. But they didnt. They kept the laser on for a miniscule fraction of a second.
If they pulse the laser fast enough, the total energy required to actually power it goes up.
Yeah, but pulsing means that the peak power draw of the weapon is lower than just running the laser constantly. It's likely going to be easier to store and move the energy over say 5 or 10 seconds than over a straight 1-second firing sequence. It also gives the debris time to clear so you're more efficient at putting all your energy into the target.
The US built a 1.25 petawatt laser in 1995 so this is not exactly a dramatic improvement in peak power, though the Japanese laser can fire for an entire picosecond while the American one is about half a pecosecond. Were talking about 1kj pulses here, and no ability to refire in a useful amount of time. They physically aren't wired up to recharge the capacitor banks rapidly.
Alyrium Denryle wrote:
The same amount of energy is still required to destroy an asteroid.
Not completely true. Higher burst power will inflict more thermal shock on the target, creating more fragmentation and effective acceleration of debris. Up to a certain point this will make it more effective then faster but weaker pulses of the same overall output energy. The actual crossover point is dependent on the composition of the target.
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It's worth noting that the amount of power required to keep a 2 PW laser on for a full second would exceed the total power consumption of planet Earth by 2 orders of magnitude.
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Arthur_Tuxedo wrote:It's worth noting that the amount of power required to keep a 2 PW laser on for a full second would exceed the total power consumption of planet Earth by 2 orders of magnitude.
You know, just run some flywheels and batteries and I'm sure it'll all work out.
His Divine Shadow wrote:Just hook up some wind power plants to it and hope the aliens decide to invade on a stormy day!
the plus side to that would be if the storm is bad enough we can use the powerplant as a weapon.
Wind turbines can't winds over certain threshold (what that is depends on design of the turbine) and will break down if not locked down.
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Elheru Aran wrote:So is the limit on actual useful laser power a matter of being able to sustain the shot for long enough for it to do much damage? Interesting...
At some point there would be severe overheating issues if you wanted sustained laser fire at that kind of power assuming there was adequate power source in the first place. So far most powerful lasers capable of sustained fire are somewhere in low megawatt range.
Sky Captain wrote:
At some point there would be severe overheating issues if you wanted sustained laser fire at that kind of power assuming there was adequate power source in the first place. So far most powerful lasers capable of sustained fire are somewhere in low megawatt range.
3 MW for 30 second IIRC is the best it gets right now; and those are chemical lasers. For true sustained fire via electrical means I don't believe anything over 1 MW has been tested. Better could be built for money, but the point gets limited since if its not portable it has little military purpose, and almost all industrial uses can be met by lasers to the tune of 10-15kw for welding, and generally 1kw or less for mere cutting. More focus is on reliability and lower cost then shear power in a lot of laser fields. Certainly gotten to be mighty diverse though.
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