Physics

Extending life of plasma channels could allow lasers to be used as lightning rods

Extending life of plasma chann...
Laser-created plasma channels could one day help divert lightning strikes
Laser-created plasma channels could one day help divert lightning strikes
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Laser-created plasma channels could one day help divert lightning strikes
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Laser-created plasma channels could one day help divert lightning strikes

Today's simple metal lightning rods may be on their way to obsolescence. That's because scientists at The Hebrew University of Jerusalem are developing a high-tech alternative that could potentially reach higher and be more effective – laser lightning rods.

When a high-power laser is shot into the sky, it ionizes airborne molecules in the process. As a result, even once the laser itself is shut off, a trail of ionized particles known as a plasma channel is left in its place. Plasma channels conduct electricity, not unlike a good ol' steel rod.

Led by scientist Jenya Papeer, the Jerusalem team successfully created plasma channels measuring 100 microns in diameter, by firing a laser in pulses lasting just 100 femtoseconds each. Unfortunately, however, after three nanoseconds the plasma cooled off and the channels ceased to exist.

In order to boost those trails' longevity by a factor of 10, the researchers added a second laser that is fired in 10-nanosecond bursts along the path of the first one. Its wider beam envelopes the plasma created by the first beam, keeping it hot and conductive. By boosting the power of that second laser, or even by adding additional beams, it is hoped that the lifespan and the length of the plasma channels could be lengthened further.

Speaking of which, though, the first plasma channels to be produced were only a meter (3.3 ft) long. The researchers addressed this limitation by creating an array of lenses that change the way in which the laser is focused. As a result, it now creates a series of three one-meter-long channels linked end-to-end, effectively forming one 3-meter plasma channel.

That said, by further adjusting the focus and using a powerful enough laser, it should be possible to produce any number of linked plasma channels, creating a lightning rod of any desired length.

A paper on the research will be presented on Oct. 22nd at the Frontiers in Optics conference, in San Jose, California.

Source: The Optical Society

9 comments
xuman
Cool man! Can we use this to beam solar energy from space to the ground?
Chizzy
put this in space and you can direct lightning to anywhere on earth.
byrneheart
Perhaps a closer possibility than beaming solar energy from space is the commercial harvesting of lightning to heat molten salt and other heat exchange tech. What is the typical frequency of attraction if the beam were several kilometres long, though the power use to create this might cancel things out :-)
katgod
Theses lightening rod should make for some nice weapons but lets continue to call them lightening rods as those pieces of metal used today all so last year.
CrazeUK
So, if high voltage electricity can go in that direction, you could also send it in the other direction? i.e. a weapon!!
DewayneCurry
Let me know when this is adapted to create Light Sabers.
PG
Light sabers eh? Imagine the ROOM you would have to fit in the handle. I suppose if you had a Tardis handle, the electronics would fit. Jokes aside,some years ago, using just this principal, an Israeli scientist developed a tabletop "Phaser" utilizing the ionizing channel created by a UV laser. He could then direct any voltage/current along that channel and effectively adjust for stun, mame, kill etc.
ACE
Sounds to me like the lighting follows the plasma channel right back to the laser, destroying the laser. Don't be the Ben Franklin holding the laser.
Slowburn
I have considered this technique for draining the charge from a cloud while the energy was still at harvestable levels. @ ACE consider shining the beam through a sheet of glass and next to a heavy cable.