# Can lightning travel on a laser beam?



## Snee (Apr 23, 2006)

Does anyone know if lighting can ride the beam of a green laser? I think i remember reading it somewhere.


----------



## Morelite (Apr 23, 2006)

Not sure about green, but I read it will on UV lasers (248-nm)


----------



## AlexGT (Apr 24, 2006)

Wow! I didn't knew that, so shinning your laser at the sky during a lightning storm would get you medium rare? or if you point at something will get hit? Nah! Where did you read this?

AlexGT


----------



## LEDagent (Apr 24, 2006)

I don't know much physics...but I do know that light are atoms which emit light when there electrons jump energy states. The light energy omitted is called a photon. If these atoms are ejected or change the electrical charge of the atoms around it, it could possible attract lightning to follow the laser through the sky.

I would believe that UV emitting lasers would have a greater chance at attracting lightning because of it's higher freqency.

...I hope I have these ideas correct...at least in principal.


----------



## Athoul (Apr 24, 2006)

It is possible to have lightning travel the beam of a laser, however it will not stike where you point but will travel down the path of the beam to the ground. If you are holding the laser, well.. you will become the lightning rod 

Of course to induce this would require a laser much more powerful then anything handheld, hundreds or thousands of Watts are required to ionize the air enough for lighting to use it as a lightning rod.

There was an aticle about this some time ago, what they did was have the beam pass a metal rod a couple meters off the ground so the lightning would travel down this, instead of going all the way to the laser itself.


----------



## cbfull (Apr 24, 2006)

Yes, this has been done using a high power UV laser pulse, it was on the science channel a long time ago.

The pulse has to be very powerful because you need to create an ionized path in the air, basically choosing the path of the lightning instead of the path being created by a chaotic dielectric breakdown (air is a dielectric until a high enough voltage breaks it down).

I don't know if 532nm can ionize air at any power, but UV is known to do this relatively easily.


----------



## Builder (Apr 24, 2006)

Lightning is the by-product of the plasma generated by the rushing of eletrons to the ground.

The Science program mentioned 14 megawatts of input power to generate their plasma.


----------



## nerdgineer (Apr 24, 2006)

While high voltage between cloud and ground can in theory induce an ionization path all the way to the ground by itself (for lightning to travel through), the ionization path generated usually consists of short hops of voltage induced ionization breakdown paths connected by ionization "paths of opportunity" which happen to be in the region when the voltage induced ionization channel starts to form. I think most often, the ionization channels of opportunity are those left behind by cosmic rays and their secondary particles which surround us constantly. The resulting random hopping of the ionization path causes the jagged path seen in lighning bolts.

A strong enough light beam - at any frequency - can create such an ionization path and help lightning form, but I don't think any normal kind of hand held or home made laser will do it. 

It requires enough power density to ionize the air, i.e. make air glow by fluorescence rather than by reflectance. Nothing like THAT has ever shown up in B/S/T.


----------



## zespectre (Apr 24, 2006)

cbfull said:


> Yes, this has been done using a high power UV laser pulse, it was on the science channel a long time ago.
> 
> The pulse has to be very powerful because you need to create an ionized path in the air, basically choosing the path of the lightning instead of the path being created by a chaotic dielectric breakdown (air is a dielectric until a high enough voltage breaks it down).
> 
> I don't know if 532nm can ionize air at any power, but UV is known to do this relatively easily.


 
I saw this one too. No handheld laser pointer though, it was a pretty hefty piece of gear.

see here
http://www.spie.org/web/oer/july/jul99/laserlight.html


----------



## tobjectpascal (May 3, 2006)

http://www.iop.org/EJ/article/1367-2630/4/1/361/nj2161.html

some information for you on it, i don't understand 95% of it but it looks like what you're talking about lol


----------



## jashhash (May 3, 2006)

Interesting. If this is possible then it may be feasable to use the power of lightning in power plants. Also....

14megawatt lazer cannons pointing straight up could provide a planetary defence against alien aircraft. This would prevent aliens from probing your minds with thier microwave beams. I say "Your" minds (not mine) because I wear a protective tinfoil cap at all times. :tinfoil:


----------



## xochi (May 3, 2006)

Is this kind of the same idea as water being a conductor only when some minerals are disoved in it but an insulator when pure?


----------



## dr_lava (May 3, 2006)

xochi said:


> Is this kind of the same idea as water being a conductor only when some minerals are disoved in it but an insulator when pure?



In a way, yes. The salts/minerals dissolve and form ions in the water, just like the strong UV ionises the air molecules. Ions can conduct electricity just like electrons, however a reaction is needed at the terminals to transfer the ion current in liquid to electron current in the wire. That is why there are bubbles at the eletrodes when you pass electricity through water.


----------

