crossing lazers

[alan2here]

Having two hydrogen lazer beams cross can results in plasma being created in the air. How many of the most powerfull sort of nexus lazers would need to be crossed\what sort of focusing optics would be required to create a human visible amount of plasma?

[insane_alien]

i think you need an energy density of 1MJ per cubic centimeter to get plasma formation. once it starts it should be able to be maintained with less lasers as the plasma will absorb a significant amount of energy from the beams.

 

also, pet peeve of mine, LASER(Light Amplification by the Stimulated Emission of Radiation) not 'lazer'.

[Klaynos]

The laser in my lab can be focussed to such an extent to do it I'm told...

 

The weirdest thing I've ever done with it is burning glass with it though, the glass actually starts emitting a broadband white light...

[alan2here]

The most powerfull hand held battery powered one I could find is.

 

http://www.dragonlasers.com/catalog/Hulk-Ultra-350mW-p-16193.html

 

at 350mW to 400mW

 

Also on the website is a small lazer forcuser that can be attached to the end and ajusted.

 

Would I need 3 crossings? This sounds a little small as then one focused beam seems like it might work and it probbably dosn't or somebody would have already noticed. I also forgot to factor in distance and that mW is possibly not the same as MJ.

[Klaynos]

The most powerfull hand held battery powered one I could find is.

 

http://www.dragonlasers.com/catalog/Hulk-Ultra-350mW-p-16193.html

 

at 350mW to 400mW

 

Also on the website is a small lazer forcuser that can be attached to the end and ajusted.

 

Would I need 3 crossings? This sounds a little small as then one focused beam seems like it might work and it probbably dosn't or somebody would have already noticed. I also forgot to factor in distance and that mW is possibly not the same as MJ.

 

It's laser, there's an s, it's an acronym!

 

You don't just need to know the power, but the power density, and how tight you can get the focus depends both on the optics you use to do it and how collimated the beam is to start with. The laser I use ever day cost around £500000, and I've never seen it cause a plasma in air, there's a focus that is under 1mm of about 10% of the light, and that doesn't do it.

[NeonBlack]

Silly English (UK) speakers spell everything with an s!

[Klaynos]

Silly English (UK) speakers spell everything with an s!

 

No, laser is an acronym, it's an s.

[Gilded]

Light Amplification by Stimulated Emission of Radiation to be exact. Same thing with "maser" (Microwave Amplification by Stimulated Emission of Radiation).